Desktop software is a one time purchase with a minimal annual support fee. It installs on your computer, so you access it there, typically a work computer or laptop. It is licensed either as a single computer install or a multi computer install network which installs on a server. It is not licensed per therapist. Every therapist can use the program on the computers that Exercise Pro is installed on and print or email exercise programs.
But, since it is not online, you obviously lose some other functions like the online client portal, video exercise, messaging pain and feedback reporting, etc.