If you have Blindsight, you can see within a specific range without relying on physical sight. Within that range, you can see anything that isn’t behind Total Cover even if you have the Blinded condition or are in Darkness. Moreover, in that range, you can see something that has the Invisible condition.
Creatures without eyes, such as grimlocks and gray oozes, typically have this special sense, as do creatures with echolocation or heightened senses, such as bats and true dragons.
If a creature is naturally blind, it has a parenthetical note to this effect, indicating that the radius of its blindsight defines the maximum range of its perception.