There are two ways that couples (or larger groups of people) can own land:
As joint proprietors. This is the most common manner of holding for people who are married or in a genuine domestic partnership. When one of the joint proprietors dies, the surviving proprietor can apply to have the property transferred to their sole ownership. Similarly, if there are three or more joint proprietors, the surviving proprietors can apply to have the property transferred to their ownership as joint proprietors. The property does not enter the estate of the deceased proprietor, and therefore that person doesn’t need to make a provision in their will for it. Furthermore, the property can only be sold with the consent of all of the joint proprietors.
As tenants in common. Tenants in common proprietors effectively own shares in the property. These can be equal or unequal shares. If a tenant in common proprietor dies, their share in the property becomes part of their estate and it is dealt with in accordance with the provisions of their will. Interestingly, a tenant in common can deal with their share of the property (i.e. transfer or mortgage it) independently of the other owner(s).