why we are not intoroduce ourself ,my self pooja

Because it is grammatical wrong... We have our right way to introduce ourselves. for example:- *I am Pooja. *My name is Pooja.

Yes, as our friend said, myself pooja is grammatically incorrect. We shouldn't use reflexive pronoun to introduce ourselves. I'm Pooja (or) This is Pooja is correct. We use reflexive pronoun to give some stress to the subject. Ex...I myself have done all the work.

Hii