What are the most common tasks/troubleshooting issues y’all run into as Help Desk support?

Hey everyone. I’m new to the IT field and got a job with the DoD (it’s a Help Desk Coordinator which I don’t even know if it makes a difference from HD support/technician/specialist…etc) and as y’all already know, they use outdated hardware there most of the time. So, I wanted to ask any of y’all who work or have worked as a Help Desk, what are the most common tasks/troubleshooting issues y’all have to deal with? I’m nervous a bit. I’ve been watching lots of vids from KevTech and Cobuman & they’ve been extremely helpful.