My tank is not filling with water. I have the float that goes up and down. Not a ball

Raise the float up manually and see if it refill. If not then replace it.

https://www.youtube.com/watch?v=IB0VHdhUR1s

Am not sure if you have a fluid master fill valve or other type Talaniman have added a nice link open that it may help you I am also adding a link of the same thing please open the link below, your problem sounds like your fill valve needs to be adjusted fill up the tank or you may need to replace the whole fill valve assembly, Thanks.

John

https://www.youtube.com/watch?v=3Q-VzqqH5dg

Not filling at all or just not full enough?

Good question Bob, Thanks.