Whichever one suits your needs.

AI studio if you want to just try it out for some code things (think of it as a web IDE)

API if you want it to use it as an API.

For business if you are an enterprise.

Antigravity

Or just you know - just go to Google.com and search for something. It's really not hard.

This instapost "wah I don't know how to use it wah" from anyone as soon as Google release a model is getting tiring - change the record please.