2 year old problems /discipline help

hm

So my daughter is almost 2 1/2 years old. She understands when we talk to her. She communicates well too. But she has terrible behavior. At home she does stuff she knows she shouldn’t be doing and I tell her firmly no but she doesn’t do it. I don’t want to yell or hit her(and have never) I know she is 2 and learning her limits. But sometimes she just goes so overboard and doesn’t listen when I tell her to stop. She has also started spitting when she gets angry/upset with me or anyone in general.

I’m not sure what to do her behavior is something I need for it to get better. I need advice on learning how to discipline her.