What is the difference between 他, 它, and 她
Disclaimer: I am a native speaker, but I am neither a professional linguist, nor have I received any sufficient grammar training beyond high school Chinese, so please take a grain of salt.

“他” would be “he” in English， “她” would be “she” and “它” would be “it". We use it exactly like that in English.

a mnemonic device: the left component of "她” is “女字旁”， which is an indication that the word is related to female.