How to get cell focus in excel?

Question

excel

Good afternoon.
How to get focus.
I select a cell with the mouse and then, if I start writing, then everything inside the cell is erased.
You can, of course, use the mouse to take focus, but how to do it using the keys.

I work in Libre office calc, but I think it will work for Excel as well.

Thanks in advance.

Answer 1

In Excel F2