You can export and reference(s) from Mendeley by 6 steps:

Steps 1-2-3: Select sources (1) from library > click on Export (2) > choose file type (3).

or

Steps 1-2-3: Click on File (1) > Export All (2) > choose file type (3).

Steps 4-5-6: Choose the export location (4) > name the file (5) > click on Save (6).

Your reference(s) are exported.