So if i learn this c# then can i be able to use unity

Answer 1

Short answer: Yes and no.
You will be able to write scripts and all, but you'll still need to follow Unity's official tutorial (or any other) for creating the environment etc. That aside, if you are planning to use Unity, learn it!!!
Good Luck 😉

Answer 2

Learning C# is just the start. There is quite a bit to learn in the Unity designer and the API.