There are two types of coownership but by far the most common is joint tenancy:
This type of coownership is usually used by husband and wife. If the buyers are joint tenants, on the death of one, the survivor is automatically entitled to the share of the one who died. When property is bought in that way, it does not matter, for this purpose, what is said in the will of the owner who dies (or whether that owner dies without a will at all). The survivor has the certainty of inheriting the share of the one who died. There can be more than two joint tenants, but the shares must be equal and the joint tenancy must be entered into at the same time.
TENANCY IN COMMON
The other type is tenancy in common. This type of coownership is usually used by business partners and coinvestors. Shares do not have to be equal but can be in any proportion the parties decide. Tenancy in common does not have the characteristic of survivorship. Each of the tenants in common can leave his or her share in the property under his or her will to anyone. If that share is inherited by someone under 18, the property cannot be disposed of until that child turns 18 without a court order. That is one risk of buying as tenants in common. It is, however, often appropriate for people not closely related to buy as tenants in common.