i have two simple c# form programs, and I want to make a button in the first program start the other form when i click it, but i dont know how to access the other programm.cs ma
You can't access a form or a method of the other program. One reason is that it's a separate program, another reason is that it's not running.
What you can do is to start the other program:
Process.Start("TheOtherProgram.exe");