The Promotional item content type is not a feature in WCMS 3.
Only Promotional items from WCMS 2 that have content in the Visibility field will migrate as blocks placed on the Sidebar(s) of the page(s) they are configured to appear on. If that field is blank in WCMS 2 (meaning that the user intended for the Promotional item to appear on all web pages of the site), the Promotional item does not migrate as a sidebar at all and must be manually recreated.
There is currently no reusable blocks available in WCMS 3, which means that if the user wants to edit the content of the sidebar (formerly a Promotional item), they must edit each side bar individually.
If you encounter a site with Promotional items available on multiple pages, let your supervisor know so that they can discuss options with the website lead prior to remediating.
To remediate Promotional items in WCMS 3, create a Sidebar with the appropriate content and attach it to the corresponding page. Visit How to create a Sidebar for more instructions.
The Sidebar content type can be attached to one individual page on a WCMS 3 site. Sidebar content generates on the right side of a page, so the existing layout will accommodate the width of the sidebar for the whole length of the page.
Note: A sidebar attached to an individual web page will not have the same title as on your WCMS 2 site. The title cannot be manually changed.