Are you talking about the grass seed heads? It's grass.

Poa annua, annual bluegrass. A weed grass as opposed to a turf grass.

Yes talking about the parts that look like seeds. if grass why would it have so many seed heads when it is s short? not used to seeing it like that

There are many different species of grass - some desirable for lawns and some just weeds. And how they grow in size and spread, when they flower and then set seed can be extremely variable depending on the species.

We use a pre emergent weed killer spring & fall that specifically lists POA as one of the weed grasses it controls. It’s so easily spread by birds, squirrels, wind & using a lawn mowing service that pre emergent is the only way to limit the amount that sprouts in a lawn. It’s too late for spring use in PNW so you‘ll need to put it down in fall then again next spring. It is an annual so you’d be preventing germination of next year‘s crop with the application of the pre emergent, if you don‘t control it the crop of POA that sprouts is larger each year.