You can create, upload, delete or assign masking categories and masking files from here only.
You can add a Masking file by choosing a masking category and masking image that must be SVG file from Select Existing Masking.
To select any pre-uploaded masking file, select its masking category from the Masking Category dropdown. The names displayed in the Masking dropdown will be as per the name assigned while creating them.
You can also create any category by just providing the name and save to create a new masking category at Create New Masking.
Similarly, you can create a new masking file by selecting Upload new masking files and assigning a category to it. It will provide options to save any masking file to use anytime.