Instant

Decals are created from the Decal Creation panel.
All four Decal types can be created without leaving Blender.

The created Decals will be added to a temporary libary called Instant. It's meant to be a temporary holding place, to collect decals and experiment with various settings.

Selection

One or multipe non-decal objects, depending on the decal type.
Nothing at all for info decals from images or text.

Add Decal to Library

Use this tool to add an Instant Decal, or any other existing Decal to any unlocked library of your choosing.

Selection

One or multiple Decals.

Keep in mind

Add Panel Decals to libararies marked as Panel in the preferences, if you want their materials to be accessible by the Adjust and Slice/GPanel/EPanel tools.

Using Create + Add Decal to Libary