“Blender signature” can mean a couple of different things depending on context—here are the most common interpretations:
1. Signature in Blender renders
If you mean adding your signature/watermark to a render, you can do it by:
Using the Compositor:
Enable Use Nodes
Add an Image node with your signature (PNG with transparency)
Mix it over your render using Alpha
2. “Signature” style or look in Blender
Sometimes people use “signature” to mean a unique visual style (lighting, materials, composition).
Lighting setups
Color grading in the compositor