You can change the maximum number of Microsoft 365-licensed users authorized for your sapio365 license directly within sapio365 itself.
Changing the total user capacity of your license will modify the amount to be paid for the subscription.
How to increase the Microsoft 365 user capacity on your license
In the back of the sapio365 main window, go to About sapio365 > License Modification. From there, you will be able to change the Microsoft 365 user capacity of your license.