Can I borrow money from the house that my mother left for me and my sister the house is paid for. The house was never in probate. She passed away two years ago. My sister is still in the house but I don't live there.

Whose name is on the deed?

Yes, whose name is on the deed. The person or persons listed on the deed will have to borrow the money

Once you two get your names on the deed, you might want to consider having your sister pay you 'rent' rather than borrow against the house. If you die or default in any other way, she could lose the house through no fault of her own.
What she would pay you would be not something in some rule book somewhere - you two will have to work out the numbers.
My advice is see what house rentals are nearby, reduce it by 10%, add up property and other taxes, add $100/mo repairs fund, and divide by 2.
So if rents are 1,000, subtract 100, add taxes + 100, and half of that is what she pays you.
The 100/month goes into a bank account in both your names.
She covers all utilities.
If she can't afford that, then borrow against it. But be careful!

Chances are that your mother's estate will have to be probated, because it appears that the house is still in her name.