A web page can be set up where donors can donate items through your website. See Solicit Items Online to add the element to your website.
Items entered online in this way are not automatically added to your item list, instead you need to accept the ones you want to promote to be added to the auction items.
Once a donation is submitted through the website, you will receive an email notification.
You can review the solicited items from the Auction Dashboard by clicking on Items -> Review Solicited Items
This page will show all the New items by default. You can choose to reject an item (which will change the status to rejected) or accept and item, which will create a new item.
Select the items you want to accept and then click on Accept Selected Items
When accepting items you can choose the item type to create:
Once accepted you can edit the item like any other item: