The term "debt financed" as a source of payment for doing the Acquisition, is it?

I have a question for word phrase "debt financed" in Acquisitions but for my best understanding, I would like to ask a question on random example: Let’s say we have three companies: CompanyA, CompanyB, CompanyC. The CompanyA is in process of acquiring the CompanyB and is considering "debt financed" type of transaction payment to complete the acquisition. CompanyC wants to give the capital to CompanyA so CompanyA can use this exact capital to pay for acquisition. My question is: What sense, if any, would it make for CompanyA to use the capital given by CompanyC? Would it be possible to pay with someone else’s capital if transaction is to be "debt financed"? I’m referring to the "help" subject: CompanyC wants to help CompanyA with money.

The reason why I’m asking my question is because of different type of payment for acquisition which is "all-stock" method. Here I understand what does it mean: the payment is done in a form of CompanyA giving some of its own stocks to CompanyB as a payment for acquistion. So any other source of capital makes no sense and it’s impossible.

But I’m not sure whether CompanyC’s source of capital, being given to CompanyA, would make any sense in case of "debt financed" payment for acquisition? I’m asking what kind of sense, IF ANY, would unexpected source of extra capital (from CompanyC) make in such case? I would appreciate as direct as possible answer please. Thank you!