I'd like to start a business as a process server. I have no experience so I just have a few questions before I get started, and would appreciate any advice at all. If anybody is or personally knows a process server that might help me out, that would be much appreciated. Thanks in advance!

I was a process server in my early 20's... I didn't have to register specifically though because I was under a different umbrella for Fugitive Recovery, and process serving was sometimes part of that.

There are RCW's that you may have already seen, but here they are anyhow.
https://app.leg.wa.gov/rcw/default.aspx ... &full=true

You are also in Pierce County and they have a website on process servers and requirements: https://www.piercecountywa.gov/3889/Process-Server