The license key library is a jar or dll that you add to your project. This library is used to load and validate your license key. This library will also enable the functionality in the iText 7 add-ons if there is an appropriate entry in the license key file.
You'll need two things:
A license key file.
The correct version of the license key library. If you're using iText 7, or iText 5.5.13 (or newer) you'll need to use version 3.x.y of the license key library. If you're using iText 5.5.12 (or earlier), you'll need to use version 1.x.y of the license key library.
To load your license key, use the following line of code:
NOTE: You'll need to call this line of code before any other iText API call. Not loading the key at start up might result in the producer line having a reference to "AGPL" instead of your company name.