Is there a way to add ability scores to attack rolls on homebrew weapons?

Hi everyone, 

I'm making a homebrewed weapon which grants +CHA modifier to attack rolls, is there any way to add this as a modifier? I can't see anything but I might just be missing it. 

Do you mean as a straight bonus, or do you mean like Hex Warrior?

Quote from IamSposta >>

Do you mean as a straight bonus, or do you mean like Hex Warrior?

 As a straight bonus, so instead of +1/2/3 it would be +CHA.

Quote from SedrisVoidtouched >>

Quote from IamSposta >>

Do you mean as a straight bonus, or do you mean like Hex Warrior?

 As a straight bonus, so instead of +1/2/3 it would be +CHA.

 Not that I cam recall. You would have to make it as plain text and the player can modify it directly on the character sheet.