Clear up % rates terms

[Mick Harvey]

Trying to understand all the percentages terms, when come to borrowing and pay backs.

I understand there is an APR that you pay banks to loan money. If you have a debt partner that wants to put money in the deal, APR still used? based on month/year or is the same? simple vs complex interest. I can calculate the ROR, is that what I can/should pay the partner? I can calculated COC return, or is that what I pay the investor and how?

Looking for examples of how would pay investor that say... is just a debt partner

I have some deals coming up and have done the calculations. I am trying to keep banks out and investors in. How do I calculate what they are getting

Thanks for all that reply