To add a note for a vendor, click the Notes tab in the Vendor Maintenance dialog box. You can use notes to record additional information about a vendor, such as an extended shipment or payment history.
You see the following text box in the Notes tab of the Vendor Maintenance dialog box:

When you finish, click Save. The Notes tab becomes yellow to indicate that a note exists for this record. If you want to add another note later, click Edit to enter additional text in the note window.