(Loan to partnership firm)

I will recieve loan from my cousin brother ( son of massi ji). I want to start new business as partnership with my wife as partner.

1) can i use loan from my cousin in my business,
a) if i open a partnership firm.
b) instead if i go for pvt ltd.

my cousin will transfer loan to my savings account.

2) do i have to pay interest to my cousin?


thank you in advance