Notepad List Prediction Trick

Hey everyone, a few years back I saw a trick on Fool Us that was pretty novel for its time, and lately I've seen a lot of magicians performing it. In the trick, the magician makes a prediction of a celebrity, an animal, or anything else.

Then they'd show the spectator a list on a notepad, usually numbered from 1 to 100, and ask them to pick one.

When the spectator called out the number, it turned out to perfectly match the magician's prediction.

I was hoping to understand how it's done.

Thanks a lot!