The licensing is based on the CRM licensing. That means the CTI for MS-CRM Integration application is locked to your CRM organization name. When you purchase the product, you need to give us your CRM organization name. You also need to purchase the same number of licenses that the active licenses you have in the CRM. If you decide to buy more CRM licenses or just activate more licenses, you also need to buy more CTI for MS-CRM Integration licenses. If you don't, your application won't work.
You can also have a per user license. It will be linked to your CRM user ID. So the CTI for MS-CRM Integration license cannot be used by another user.
The best way to organize your license is to place your license file on a common share folder and then configure each client to point to that file. Then if you need to update your license, or if you buy more licenses, you can just replace that file and you don't need to update it to all clients.
To get a CTI for MS-CRM Integration license, follow the instruction of the Get a new license chapter.