The person extending a covenant is called a covenantor and the receiver, a covenantee.
They are very common in real property dealings and are used to restrict land use such as amongst shopping mall tenants or for the purpose of preserving heritage property.
For example, a covenantor to a mortgage commits themself to pay the mortgage if the mortgagor defaults. A person buying a property may find that there is a covenant prohibiting dog ownership on title.