Updating to latest OS from Mojave

Hi I have a 2018 iMac running Mojave 10.14.6 3.6 ghz i7 16GB ram Radeon pro 560 4 GB. I’m going to be updating to the latest OS. I am backing all my files up to external drives but I’m wondering if anyone has advice on anything else. I should be concerned about or looking at the media files? They may be changing locations, applications? Thanks for any advice.