what is the difference between vgexport and vgremove

The man pages says:

With vgexport you remove all VG configuration from the system without touching the disks itself, this means all data will remain on the disks.
With vgremove you first have to remove the LVOLs, then the VG itself.
This will remove the VG definition from the system and the VG structure (including data) from the disks.