Who Called My Phone?

How can i change my phone to show who is calling?

I have a verizon enV 2 and for a while now when people call it says No ID.
How can i change it so i know who’s calling? Why did this happen?
Even when i have missed calls it says that and i never know who called.

There is probably a setting in the Settings area of your phone. If you don’t have a manual for your phone. Google enV2 Manual. That should bring up a link to be able to read the manual online to find out how.