How to use "&" in Menu Items (WPF)

Question

I don't know what is "&" called, but I want to add to a WPF menu item like this &Search so when we hit Alt, a small line will appear under "S".

See picture below:

Answer 1

This is called an accelerator key. In WPF it's used by the _ character prefix.

For example: _Search, Hel_p Favorites, etc.