Before doing this you need to know decals are made using texture maps which are base maps, height maps, and normal maps.
A Decal dynamically applies textures over an underlying texture. This can include bullet holes, blood spatter, dust, etc. Shoot a wall, for example, a decal of a bullet hole will appear at the point where your bullet struck.
In the first step, we will create our own decal, to do this go to Game Object<Rendering <HDRP Decal Projector.
To make your Decal projector work create your material and assign the base map, and normal maps.
Select the decal we create early and drag and drop the new decal material we create into the decal projector.
Then create a cube and make sure the z rotation of your decal is 90 and move the decal box while the bottom part touches the cube.
Now I will download premade decal from filebase
Create a sphere and make sure your decal z-axis is at 90 degrees and the material of your decal is set to HDRP/Decals.
See you in the next article.