If you are purchasing property with another person, or other people, then you need to choose whether to purchase as tenants in common, or as joint tenants.
Joint Tenants own the property equally, in fact joint tenants each own 100% of the property. While this is mathematically impossible the law has created this misnomer, when one joint tenant dies the entire property passes to the other tenants before the Estate or the Will kicks into effect. Commonly joint tenancies are used either for married couples, or for parents who are purchasing a property with a child and wish for the entire property to pass to the child on their death.
Tenants in Common can own the property in specified percentages, they don't have to own equally, and the inheritance of their share is dictated by the Will. If you wanted to set up your Estate so that on your death your part of the property was held in trust for your children then you would need to purchase the property as Tenants in Common, or convert an existing property from joint tenants to tenants in common.