You should always download and fully test the evaluation version of PDF2XL before you purchase to ensure it is the right option for your needs.
Once you've tested it and verified that you would like to purchase the full version, you will need to activate from the evaluation to the full version.
Here's how you can do that:
When you install and log into PDF2XL before purchasing a license, the splash screen that appears when you run the application will show the options for the Evaluation version:
Notice there are two buttons on the bottom:
PURCHASE SOFTWARE to buy a full version, if you haven't already
CONTINUE EVALUATION to keep using the evaluation. You will need to use this option to get to the next step, even if you've already purchased your license.
To switch your application from an evaluation to a full version, you will need to log out of the evaluation version using the "Log out" option on the Start menu:
Log back in with the same email and password you used for your evaluation version. This will activate the full version.