Consider the mechanism, the material, and the style when choosing sliding closet doors.
The simplest mechanism is the bypass sliding door. The doors are suspended from an overhead track. They are kept in place with a locator track on the bottom.
There are normally two tracks, next to each other. They allow half of the width of the sliding doors to be opened at any one time.
To provide a wider opening, three tracks can be used. Each section of three doors can be slid next to each other, so that two-thirds can be opened at any one time.
The alternative mechanism is the sliding folding door.
This consists of a number of vertical door panels, which are hinged to each other. Each is suspended at the top from an overhead track.
They can then be opened with pairs of doors folding into the room.
This type of mechanism is rather more complicated and has more possibility to fail. It has the advantage that the whole width can be opened up at the same time.