Throwing things, Screaming, Hitting Self, Putting fingers in mouth... How to stop such behaviours?

My 23 months old toddler keeps throwing things, screaming or whimpering when things don't go her way. When reminded gently or reprimanded harshly, will hit others or self and start putting fingers into her mouth. Is this a phrase that will pass or is she exhibiting such behavioral issues which need professional assistance? (This has been ongoing for a couple of months and no matter how we coax, persuade, explain or scold, she just vent her anger and frustrations by throwing tantrums etc.) From other posts, it seems like younger child 15 months to 20 months will tend to do that but she is already coming to 2 years old! Some say ignoring them will destroy their confidence and sense of security, while others say don't give in, ignore and just let them cry it out. Feeling abit helpless. #pleasehelp #advicepls