Newbie question: How to turn my house into a investment property?

[Robin Naggi]

Hey everyone, 

I’m new to BiggerPockets and house hacking in general. 
I recently tried to get a pre approved for a loan on a BRRRR property.
I was only approved for a 280K loan, due to my debt to income ratio being too high even though I have a 6 figure salary. I currently have family living at my house and their rent covers my mortgage each month.

I don’t have any rental agreement set in place.
I don't have a LLC. The property is in my name.

What do I need to do to get a higher loan amount?

Thank you