Magic is not magic, and money cannot be "changed" for no reason.

Magicians have two commandments: don't reveal magic secrets, and don't spend money to teach magic.

So I can only tell you the direction:

First, pure technology (such as changing money from big to empty-handed)

Second, use props (original props will be much stronger than shanzhai, such as: the dollar changes, money becomes a credit card)

If you want to learn the whole set of "changing money magic", you can consult a professional magic training institution ~