Apprentice ASK: what is the difference betweem margin

account and regular account. Does margin account have to pay more gain tax than regular ones. If one has a margin account, can she do normal trading like that for regular account? Because I am new trader, I don't know too much about the rules of trading. This week I was warned by my stock company for a free ride and they suggest me to change my regular account to margin one. I am not sure how it works. So ask masters here to give some hints and instructions.

Thank you in advance.