Shadow maps are essentially textures projected from the point of view of the Light. Universal RP uses a bias in the projection so that the shadow casting geometry does not self-shadow itself.
In Universal RP, each individual Light component controls its own shadow biasing using the following parameters:
Find these settings under the Shadows section. If properties are not visible, change the Bias setting from “Use Pipeline Settings” to “Custom” to expose them.
Using high shadow bias values may result in light “leaking” through Meshes. This is where there is a visible gap between the shadow and its caster, and leads to shadow shapes that do not accurately represent their casters.