In short
A title deed is the official document showing ownership of a property. In Turkey deeds are distinguished by construction stage into land title, construction servitude title and freehold title; and by ownership structure into sole title and shared title.
The first distinction shows what stage the building is at. A land title has no individual units defined on it yet. A construction servitude title identifies a unit in a building still under construction. A freehold title is issued once the building is complete and the occupancy permit obtained, and it is ownership in its fullest form.
The second distinction shows how many people hold the property. Under a sole title one owner holds it outright. Under a shared title there are several co-owners, and each holds a proportion rather than a physical part. Co-owners have a statutory right of pre-emption: when a share is sold to a third party, the others may acquire it on the same terms.
Why it matters to an investor
The type of deed directly determines how easily the property will sell and whether it can support a mortgage. Under a shared title the sale cannot be run alone, pre-emption applies and the pool of buyers narrows. If a building stands on a plot held under a land title, that building has not been registered on the deed, which is a separate matter to examine on its own.