I have had my performance review 2-3 weeks before we are supposed to have our annual salary increases. The review went well and I was promised an increase. No amount was specified, but I am sure of an increase.

I Just want to find out, if you as an employee are supposed to get a formal offer document from your employer regarding the amount of your increase, whereby you sign it or you decline it? (My increase is getting paid in about 3 days and i still have no communication on amounts or anything)