Step 1: Click on "Settings" (gear icon) in the top right corner of any page.
Step 2: Click the Custom Fields header.
Step 3: Click the "Add" button in the Vendor Custom Fields card.
Step 4: Select "Vendors" on the left side of the screen.
Step 5: Locate vendor and click the "View Details" tab in the lower right corner of the vendor box.
Step 6: Select the "Add custom fields" link in the lower right corner. If there are already custom fields added, you can select the edit (pencil icon) button in the lower right corner.
Step 7: Type in the information in the fields and click the blue "Save Changes."