Brand is the name the product is sold under on your site. For example, Nike.
Vendor is the distributor with whom you place orders. For example, Running Shoe Distributors.
*Note that in Shopify, the Vendor field on your product page will show as the Brand in Inventory Planner.
You can configure your Shopify connection to import your Shopify Vendors as suppliers to Inventory Planner.
This is done via your accounts "Connections" settings:
Find the Shopify connection and click the "Connection Settings":
You can then select the option, seen below:
Once you have checked this option, Click "Save".