Decal Creator Pro includes an automatic transform check that applies all required transforms for you. Simply enable the Apply Transforms option in the add-on, and it will automatically apply location, rotation, and scale before creating the decal, helping prevent borders and alignment issues.

Ensure the active object has no material. If it has multiple materials, select the object, switch to Edit Mode, select all faces, and assign the desired material.

Yes, you can. Make sure to link your texture or any node output to an emission node to prevent shadows or artifacts.