The OptiPlex 7000 SFF has one 2.5-inch drive bay
One internal 2.5-inch SATA bay accepts a hard drive or SSD. Not a lot of secondary storage, but enough for bulk data alongside the main M.2 SSD.
One internal 2.5-inch SATA bay accepts a hard drive or SSD. Not a lot of secondary storage, but enough for bulk data alongside the main M.2 SSD.