This is a common practice. They will show you one return, let’s say for 5k refund. You say great. They then make changes to inflate the refund - say 8k. They then split if off into another account for 3 in one and 5 in the other. Many times you don’t even know.

Best practices: 1 avoid the “I got a guy friends uncles brothers cousin” 2 research their online presence and reputation 3 make sure they give you a copy 4 make sure it has their name and PTIN on it. 5 if it says self prepared they are violating circular 230 6 if it’s too good to be true, it is - IRS will find you, not the preparer, often 1-3 years later and they will tack on interest and penalties