Living in our family house after mom passed away,I'm paying all the bills,can I buy our house and pay out their shares towards them? What's my legal rights as I am the youngest sister,last to get married.

The fundamental question is: who is the current owner of the house? After your mother passed was the house retitled with you and your sister as joint owners? If your sister is a co-owner you can cetainly make an offer to buy her out. If she refuses to sell you then need to reach an agreement with her over who will pay the taxes, utilities, insurance, repairs, etc.

Current owners,its three sisters which includes me,two living under its roof,one has her own,sister I'm living with do not contribute to any past payments or future payments,or would fix any maintenance,its sad to see my moms house neglected like this,therefor I would want to buy it if There's a possibility cause I'm willing to fix everything that breaking

You can certainly buy out your sister's shares. It would be the smart thing to do before you sink money into the house.

We as sisters signed titles of ownership yes,got the paperwork How do I set up an agreement? Where do I go to do this?

I do understand they can decline of me buying the house too...

You get an attorney or realtor to draw up a contract of sale.

But yes, they can refuse to sell, so you then ask them to buy you out.