When i first ported over to public mobile I lost my mobile data because I didnt even know I needed to add the APN. Had to borrow a friends phone to troubleshoot.
Would be nice if public mobile included a little paper with the APN settings. They could make it cute like their other material with a little dude yelling "HEY follow these steps to make sure your data/internet is activated with your new sim! Or even print it on the back of the "credit card" the sim card comes in. Also a link to ios/android instructions on changing APN.
Even a regular white paper would be ok to keep costs down, had some issues with my phone and had to do a reset. Forgot to write down the APN and was stuck with no data until i could get to someone to let me borrow their phone again. It was my bad for not writing it down but it could help so many people less techy than me to figure out a solution before they give up on or bash public mobile or even to keep them from having to come here or google for help.