How to do tax return on 25/75 partnership

Hello,

I am purchasing a rental where I put 25% of the money and my mother put the 75%.

There is no LLC, etc. The county registers the equity percentage.

I was thinking about doing a K1 but it seems to be for legal structure / LLC stuff.

How do you show you own and receive x% of rental income expenses and depreciation on a tax return ?

Thanks in advance,

Charles