(The advantage of an expanded serial number over multiple serial numbers is that one need not track the assignment of serial numbers to users.) Send your request for an expanded serial number to Obtain a Network Named User (NNU) license, and install a local license server.
Each user will require an account on the Embarcadero Developer Network (EDN). Each user can install Visual Assist to three hosts before requesting to that a host be deactivated, or count increased.
However, there are no upgrade options, which means if you plan to upgrade to the next major release, you'll have to buy it at full price. One-time purchases are available for both PCs and Macs. Office 2021 is sold as a one-time purchase, which means you pay a single, up-front cost to get Office apps for one computer.