This is a moth, most likely a plume moth or a small grass moth (family Crambidae or Pterophoridae). Here's what the image shows:

Based on the fringed wings and banded abdomen, this looks like it could be a Crambid moth (Grass moth) from the family Crambidae - these are very common household moths that rest on walls at night, often attracted to lights. The heavily fringed wing margins and the pale yellow/brown coloring with the striped abdomen match this family well.

It could also be a plume moth (Pterophoridae) - though those typically hold their wings at a T-shape when resting.

Is it harmful? Generally no - adult moths don't eat or damage anything. If it's a Crambid/grass moth, its larvae feed on grass roots outdoors and are not a household pest concern.

If you want a more precise species ID, a clearer/closer photo and knowing your geographic location would help narrow it down significantly. Apps like iNaturalist are excellent for free insect identification.