Just had carrier update pop up when downloading new software says it downloaded successfully but when u go into settings>general>about then click on carrier says PRL 1 what it mean anyone help

You don't need to tap on Carrier to see the new version.
Tapping on it does nothing anyway unless you have WiFi calling turned on in which case it show the IMS status (normally Voice and text).

PRL stands for Preferred Roaming List.