Many larger companies not only continue to use paper mail, but send money that way. Thus, digital nomads or address flexible small businesses may benefit from a paper mail to digital media conversion service known as a Digital Mailbox Service.
Many companies offer services ranging from scan and email, to scan and store, scan and sync images to Dropbox or Google Cloud Storage, even forwarding services where they can forward the physical mail to your new physical address.
One of the most important services is digital or mail deposit of your checks to your bank. If your bank allows mail deposits, you may have the customers send those payments directly to the bank itself. However, synchronizing the deposit to the invoice may be a bit messy. Some accounting services will handle that process for you, usually billed at a percentage of deposits or a flat per check or entry fee.