The article outlines the steps How to upload vendor documents. (Please note to perform this action you require the "manage customers and vendors" permission)
FOLLOW STEPS BELOW:
1. Via the Navigation pane click Administration->Vendors
2. Double click on the vendor you would like to upload a vendor document for.
3. Click and open the Documents tab.
4. To add a document in a specific location on your device click the green plus icon
5. Alternatively if you have a document in your clipboard currently to add this click the clipboard icon.
NB. For a quick tutorial watch below
