Can someone please tell me what kind of frame this is

It is a likely steel frame, painted in faded yellow paint. No decals suggest its been repainted or stripped for some reason. The cranks are painted too suggests a repaint or a low cost bike.

The BB is a ashtabula. Pedals look to be possibly a 1/2 pedal thread. Headset is threaded. There are rear brake mounts visible, but brakes are missing. I don't see any front brake either, they would have been single-pivot calipers based on the one hole.

The pedals appear to be regular flats of a budget plastic construction. If they don't spin freely you will need to strip and clean the bearings+races on the inside.

You'll need a lot more parts before its rideable. Wheels tubes tyres, brake calipers cables and levers, bars and stem, grips, seat seatpost and pinch bolt.

The chain may not be savable, a replacement would be advisable.

The dirt implies its been in the ground for a while, which may be good or bad. Need to look all over for rust, and remove/treat whatever has formed already.

Now what's your goal for your BMX ?

Looks like one of the original T-1 TerribleOne frames. However the 1 piece cranks and threaded headset with press-in loose bearing cups suggest it is much more inexpensive frame destined for the trash.