There are several online mailbox options for full time RVers who need a real physical address for license, domicile, etc.
We use Traveling Mailbox. All mail that arrives gets scanned (just the front of the envelope) and shows up in our Inbox online. From there, we can request an open and scan, so the contents can also be viewed online. Or we can have one or more pieces of mail forwarded if it's something like a check, vehicle registration, etc.
We can have packages sent there also, but it doesn't make sense to pay postage twice. So, when we order from Amazon Prime (or whatever), we just have things shipped to wherever we are. If we're a couple days from moving camp, we just ship to our next location. About half of the places we've stayed have packages waiting for us when we get there.. ?
If you require an address in your home state, you may have to shop around for a mail service that has an address in your state. If you can “move” because your employer doesn't care where you live, or you're retired, many chose to move their domicile to a tax-friendly state like Florida, Texas, or South Dakota. Escapees has a great article on how to accomplish that.