The money comes from the business as a loan expense. IF YOU DO NOT PAY back the loan you will likely be held personally responsible
Paying back a loan is never a deduction.
However, the interest paid is.
If you borrow $15,000 and pay back $16,000, you would have a $1000 tax deductible business expense.
It's a loan for the business so the interest is a business expense. Repaying the loan is repayment of capital
A loan is a liability. Interest is an expense. You presumably used the loan either to pay expenses or purchase assets.
Depends on how the business is legally set-up. If it is a sole-propriator, then company $$ & personal $$ are the same. If it is a corporation, then the two are separate, & the loan should be paid back out of the earnings of the company, & then expensed.
By handing it to the person you owe it to.