What is the difference between Func and delegate?

Question

I see delegates in two forms:

A. Func convertMethod = lambda 

B. public delegate string convertMethod(string value);

Answer 1

A initializes an instance of a delegate (that can be called immediately). It's a variable of type Func< string, string >.

B specifies the definition of a delegate (its signature). It can be used to later define variables of type convertMethod.