Projecting Debt on 3FS

Hi, I am currently trying to value a company and I'm wondering if anyone had any tips on projecting debt on the financial statements. I know the following questions are largely company specific, but would it be fair to assume that a company would take on no debt and just continue to pay down its debt with time, and is it acceptable to assume that the company might take on more debt as its only source of financing (given the company is already highly levered, and if yes, can I just assume that the company might borrow $100 mil (given that there is no actual announcement that the company would borrow that amount, and I am not sure how much the company would borrow, if it decides to borrow in the first place. it's just that by borrowing the $100 mil it would be easier for me to complete my balance sheet.) I know that the last question sounds illogical, but I am rather new to valuation and I have no idea how else to proceed and I could use all the help I can get. Thank you!!