You cannot delete a vendor/supplier at this time, but you can make one permanently inactive.

To make a vendor inactive

  1. From the left menu, select Expenses then Vendors/Suppliers.
  2. Click the arrow on the Action drop-down menu beside the vendor/supplier you want to make inactive.
  3. Select Make inactive.

Instead of making them inactive, it's better in some situations to merge accounts, customers, vendors, or suppliers instead.