Can I register my account through my business entity (LLC)?

Yes, but be aware you MAY have to pay professional data fees. It depends on your business structure and it is a bit of a gray area. You also need to decide before you begin your practice account. You can not change your mind later.  

CLICK HERE for more information.  

Warning: Do NOT engage in any trading activity with money you cannot afford to lose. Day trading can be extremely risky and offers no guarantee for success. You should not fund day-trading activities with retirement savings, student loans, second mortgages, emergency funds, funds set aside for purposes such as education or home ownership, or funds required to meet your living expenses. 

If you engage in day trading activities, set a budget and do not spend beyond your set budget.