Vendor is defining as supplier of goods or services. Normally, a vendor will sells the products or services to another company or individual. Vendor Field also provided in field mapping. 
For this part also provided some settings over there such as :
1. Append Prefix / Postfix on Feed
Append the prefix / postfix on feed will let you to add some wording that you want to be added or updated for the product. Its support with characters and symbols.
For example:
A. Adding SKU: as Prefix in the vendor field
| Value in feed | Result |
| CB34575 | SKU: CB34575 |
| AB645856 | SKU: AB645856 |
| Nike | SKU: Nike |
B. Adding Collections as Postfix in the vendor field
| Value in feed | Result |
| XES | XES Collections |
| Adidas | Adidas Collections |
| Nike | Nike Collections |
2. Ignore Words
Ignore words lets you ignore the specific wording that you don't want to be added or updated for the product. Its supports multiple ignored words, separated by a comma while its also support regular expressions too.