I just purchased more storage and it’s still saying my storage is full why is that

There is no option to upgrade the iPhone internal storage, it is built into the model you buy. The iCloud data storage is saved to Apple’s sever. You can however, move data like photos to iCloud and then delete them from your iPhone to free internal storage on the device. Be sure to disable iCloud photos first so they don’t delete from your device and the iCloud server.

settings > tap your name > iCloud > photos and turn off iCloud photos. Once your done deleting turn it back on to have the ability to save new photos to iCloud in the future.