Can we program android apps directly on our smartphone?

Yes.
but why?

@magicMirror because I'd like to program apps on my personal android phone.

I used AIDE years ago on my Samsung Galaxy Mini 2, not a great experience though, would be better if you use it on a tablet.

https://play.google.com/store/apps/...

@volttide but that is paid, any free app?

@VIRAJ08 wow it was totally free back then, I don't know any alternative yet.

@magicMirror there are billions of people that aren't as fortunate as you. Did you know for example that the YEARLY income of an average worker of Nepal is probably less than the worth of that of your work laptop? And than be a 15 year old whose only chance to succeed is to use his/her smartphone to learn how to code. And you get questions like these. 🤷‍♂️

@heyheni 15 year old?

You might code using a website like codesandbox and using react native.

@Flamestro Thank You Sir 😊

@heyheni fully working computer setups are being thrown in the garbage all the time

@volttide @VIRAJ08 It seems to be free for me?

I like to say "Yes'nt".
It's doable, but not particularly good.

Give this a try:
https://play.google.com/store/apps/...

I remember there is an app that allows you to make apps directly on your phone by drag and drop. I forgot its name.

MIT App Inventor.
I tried, I succeed, I left.

@ScriptCoded really? But it tells me to buy premium for full access

Depends on the app, depends on the phone

@volttide As an alternative I used Java NIDE, free and open though not maintained anymore unfortunately. I'd say it's the only well-made Android IDE I've seen without any bullshit

@VIRAJ08
You are using Cyclic logic. "We want to because we can!"
let me put it another way:
"can we shove a sharp sticks into our eyes?"
"yes we can. but why would we do that? it sounds really painful - almost as painfull as coding android apps on an android phone!"

If you decide to go for it, at least buy a cheap keyboard and a USB adapter for whatever your phone has.