Sibling and I owned a house together. Sold it in 2018, bought a new one in 2018. Both names on mortgage. How do we handle Sale of Principle Residence?

Sibling and I both owned a house for about 7 years, principle residence for both. Both names on mortgage.

Sold it in 2018 and bought another in 2018, same arrangement.

How do we handle the Sale of Principle Residence on our separate tax returns?