If you purchase a freehold property in England or Wales, you will own the home and the land it is built on. However, there may be a freehold company who owns the estate areas, such as the communal parts or gardens.
If you buy a leasehold property you are buying the rights to live in a property for a set period of time. You do not own the building structure or the grounds it is situated on. Most flats are leasehold.