Is it correct to use will after if when offering something?
As a general rule, in a condition if is never followed by will. However, use will after if to emphasise that it is not just a condition, but that the other person may accept or decline your offer.
For example, a phrase like this: If you will write the article, I will attend to something else.
(you will be asked to create an account if you do not have one)
Learn more simple rules