The library is the place where resources/materials/information is stored so that these resources/materials/information can be used by the people. PrintXpand designer tool offers you such libraries in the backend like a color library, font library, image effects and filters library, and clipart library. In these libraries, you can store the related information so that it can be used by your customer on the front end.
For example, if you add a font to the font library then such font can be applied by the customer on the product.
These features help your customers to garnish the products as per their requirements.