Btw Chess.com isn't the best place to ask this question. You should probably post things like this on a programming forum, like Github Support Community.
We want to share a Python Program

If this program is related to chess, I believe this is a good place to share it. And I also offer you to chose Github.

What are the platforms different for each is apps
1 windows 10 firefox
2 android chess.com app google browsers
3 iPad chess.com google and safari browse

I agree with the GitHub suggestion. There are other similar options like GitLab and BitBucket, which are also good (it probably doesn't matter much which of them you choose).
On the other hand, I would stay away from SourceForge and other similar hosting platforms.

I agree with the GitHub suggestion. There are other similar options like GitLab and BitBucket, which are also good (it probably doesn't matter much which of them you choose).
On the other hand, I would stay away from SourceForge and other similar hosting platforms.
What is your reason for staying away from Sourceforge? (There could be many, and none may apply to the present case.)
My friend wants to share a python program he created but we don't know the best way to do it. What do we do?