Which AI app should you use first

You have decided to try AI. Now the store shows you five apps, and each one asks for something. An email address. A code sent to a SIM that belongs to your brother. Space on a phone that is already full.

This lesson picks one app for you. The choice comes down to your age, your phone and whose SIM it is.

The AI that is already inside your phone

WhatsApp is on almost every phone around you. In India, WhatsApp now carries an AI assistant called Meta AI. There is nothing to install and nothing to sign up for.

That makes it the easiest way in the country to try AI today. No email. No new password. No storage needed, because the app is already there.

Look inside WhatsApp for a chat or a circle marked Meta AI. Open it like any other chat and type your question. Try this one first, because it needs no facts from you:

Rewrite this as a short, polite message in English.
Do not add anything I did not say.
My words: order is ready, please collect it today evening.

A good answer comes back in a few seconds and looks like this:

Your order is ready.
Please collect it today, in the evening.
Thank you.

You may have seen older videos telling you to save a number and message ChatGPT on WhatsApp. That does not work from an Indian number any more. Meta changed its rules in late 2025, and Meta AI is now the only general AI assistant inside WhatsApp in India.

One honest point before you start. Meta AI sits inside a Meta app, under Meta’s own terms. The lesson on what you must never type into an AI applies from your very first message.

Meta AI is a good place to start, not a good place to stay. It sits inside a chat app, so longer study work gets awkward. When you want to give it a photo of your notes, move to one of the apps below.

Your age decides which apps you may use

Each company sets its own age rule. They are not the same, and the differences matter for this course.

Gemini needs a personal Google account, and you must be 13 or over. A work or school Google account is not the same thing. Those need you to be 18. ChatGPT also allows 13 and over. If you are under 18 on ChatGPT, you need permission from a parent or guardian.

Claude is different. Anthropic’s rules say you must be 18 or older. There is no parent permission route at all. So a 16 year old cannot use Claude, and no setting changes that.

Give your real date of birth when you sign up. ChatGPT now also tries to guess whether an account belongs to someone under 18. It looks at how the account is used, not only at the date you typed. An adult account can end up in the teen version by mistake. Getting it removed means proving your age with a selfie or a government ID through another company.

If you are 13 to 17, there is a timer you cannot see. ChatGPT may ask you to prove your age in the same way. You get 60 days to finish that check. After that, ChatGPT switches your access off. So sort out your parent’s permission on the first day, not on the sixtieth.

There is one more thing that confuses people. On the Indian Play Store, ChatGPT, Gemini and Claude all carry a rating of 12 and over. That store rating is not the company’s rule. The rule is in the terms you agree to when you make the account.

Claude wants a code on a real SIM

Claude has one more gate that stops people, and it is worth knowing before you start. Making a Claude account needs a six digit code sent to your mobile number by SMS. India is on the supported list, so an Indian mobile number works.

What does not work is an internet calling number, a number made inside an app, or a landline. Anthropic rejects those. There is no way to skip this step.

Gemini asks for much less. If you already have a Google account on the phone, you are most of the way there. Some parts of the Gemini website even work without signing in. Stuck at a sign-up screen? Read how to sign up with no email and no SIM.

What will actually fit on your phone

Before you compare apps, spend two minutes on your own phone. Two numbers decide most of this choice. You need your Android version and your free storage.

Open Settings, then About phone. Look for the line that says Android version and write that number down. Then go back to Settings and look for Storage. Write down how much space is free.

Google says trouble starts when less than 1 GB is free on your device. If you are below that line, clear space before you install anything. Deleting old WhatsApp photos and videos usually frees the most room.

Now the app sizes. Most people assume the famous app is the small one. It is the other way round. These sizes were checked on 9 August 2026.

Gemini downloads at about 6 MB. Claude is about 26 MB. ChatGPT is about 91 MB. Microsoft Copilot is the biggest at around 200 MB.

On a phone with a full storage bar, that ordering decides everything. If your free space is near the 1 GB line, a 200 MB app is not a small choice.

Now the part that catches people out. The apps also need different Android versions, and the order runs the opposite way. Gemini needs a newer Android than ChatGPT does. So the smallest app is often the one that will not install on an old phone. Of these four, the one that works on the oldest phone is ChatGPT, and it is one of the biggest.

Roughly one phone in twelve in India runs Android 10 or an older version. If your phone is one of them, you are not alone. You still have a way in, and this lesson reaches it below.

Do not try to work this out yourself. Open the Play Store page and let it tell you. If it says the app is not available for your device, that is the answer. Do not hunt for the file on some other website. Use the browser instead, which is the next section.

That message can also show up on a phone with a new enough Android. Google only supports devices that carry its Play Protect certification. Many secondhand and unbranded phones do not have it. You can check for it in the Play Store settings, on the About screen. The browser route needs no certification at all.

Size matters after you install, too. When an app misbehaves, people tell you to remove it and install it again. On ChatGPT that download is about 91 MB. On Copilot it is about 200 MB. That is a large piece of a daily data pack. Keep it as your last idea, not your first.

Copilot deserves one line. Its free level includes voice, and a camera mode where you point the phone at something and ask about it. That is genuinely useful. It also costs you around 200 MB of storage, so it is not a first app for a full phone.

You can install nothing at all

You do not have to install anything to use these tools. Open Chrome on your phone and type the address instead.

gemini.google.com
chatgpt.com
claude.ai

This route uses no storage. It also suits a shared phone, because you can sign out and leave nothing behind. If you are using your sister’s phone or a cybercafe machine, this is the safer way.

One warning goes with a shared machine. If a page says the tool is not available in your country, do not go looking for a VPN. India is a supported country for ChatGPT, Claude and Gemini. A VPN is usually the cause of that message, not the cure. Both OpenAI and Anthropic warn about this. Reaching their services from an unsupported location can get your account blocked.

The browser is not free of cost in data terms. Pages still load, and answers still travel over your pack. If your daily pack is small, read using AI without finishing your data. It has the settings and the habits that help.

Free is real, but it is not unlimited

Every one of these apps has a free level. Every free level also has a limit, and none of the companies publish an exact number of messages. If a video tells you the exact count you get per day, ignore it. That number was a guess, and it goes stale in weeks.

When you reach the limit, the app tells you on the screen. Look for a time in that message, not a number. The time is when the tool comes back for you.

Google explains Gemini’s free level this way. The limit refreshes every five hours, until you reach a weekly limit as well. So there are two limits behind that one message.

On ChatGPT’s free level, making pictures and uploading files have their own separate limits, apart from the chat limit. So an afternoon spent making pictures can cost you the chat you actually needed.

Two more honest points. OpenAI says ads may appear in the free tier in some countries, and it does not list which ones. An advertisement is not the AI’s advice to you. And when you hit a limit in the middle of work, copy your unfinished text out first. Then switch to the other free app rather than sitting and waiting.

So which one should you open today

Here are the four easiest apps side by side. Copilot is not in this table, because at around 200 MB it is not a first app. Read the row that matches your age, then look at the size column.

Sizes and rules were checked on 9 August 2026. All of them move. The Play Store page and the sign-up screen are always more current than any page you read, including this one.

The store will show you other names too. Grok is rated 18 and over on the Indian Play Store, which is stricter than the rest. DeepSeek is free and its answers are good, but its servers sit in China. India’s Finance Ministry has told its own staff to avoid AI tools on official devices. That advice named ChatGPT and DeepSeek. Neither one is where you should start.

Here is a plain recommendation, and it is only a recommendation. If you are under 18, start with Meta AI inside WhatsApp or with Gemini. Both are open to you, and neither needs a SIM in your own name.

If you are over 18 and you want the best free help with writing and study, add Claude later. Add it once you have a mobile number that is genuinely yours, because that choice is permanent.

Whichever one you pick, you get more than you expect. Each free level already does more than a beginner needs. Claude’s free level includes voice, with a push-to-talk setting made for a noisy room. Gemini’s free level includes pictures and live voice. If you would rather work in Hindi, read using AI in Hindi after this lesson.

Do not install four apps. Pick one, use it for a week, and learn what it is like. When it fails on you, read what to do when the app does not work. It covers the eight things that actually go wrong.

You now have an app open. The next question is what to say to it. That is lesson four, your first ten questions. It gives you ten things to try that return a real answer. Before that, do the short practice task below in the Play Store. It takes ten minutes and it saves you a wasted download.