Can someone help I don't know brand of bike mine is?

All we can see is a logo of a B with spikes to the left, a top tube reinforcement plate which implies a BMX as does the fork with no visible brakes, and a matt-black rattlecan spray paint job. I don't recognise the logo, but someone might.

Sadly a bike getting sprayed like this is normally because its not worth a good paint job, so if you're expecting a hidden treasure underneath, you'll be disappointed.

I'm guessing you're not the person who did the spraying, so try asking the bike's previous owner (ie whereever you bought it from)

You can also have a close look at the sides of the downtube and look for a sticker/decal under the paint. Its not unusual for a lazy painter to leave all the stickers in place.

If you want to get a set of decals made that says "hardy bros" and stick them on, then go ahead. Your bike is your bike, and you can do to it whatever you want. The exact brand really doesn't matter.

It looks a lot like the logo for BlackEye bikes.

They seem to have two different styles of the letter "B" in their logo.
The one that looks the most like the logo in your picture looks like this

BlackEye Killroy

The other style of "B" appears on the header of their web page. The backwards facing arrows are more pronounced

Here is a bike in the wild from bmxmuseum.com with the same logo