Can't get into my new phone Recently I purchased an android phone from my local second hand store and they showed me It was working but when I got home and I tested it out it would not let me use it because it said I had to sign in with the previous owners account. How do I sign in with my account?

Thanks,
Asher.
If you can't get into Settings, most phones have a way to factory reset with hardware buttons. You can probably find it with some googling.

If it's a Samsung phone, depending on the model, you can use Smart Switch to do an "Emergency software recovery and initialization", which completely reinstalls the phone's most recent software and firmware. Maybe other brands have something similar.