If you need to find which license is associated with a particular device, you can do that by opening an app such as Word, Excel, or PowerPoint on a device and select File > Account > About Word.
From the About Word page, the license ID is listed as either License ID or Product ID as in the screenshot below.
Match the digits of the ID in the app with what appears under the License ID column on the account portal (or admin portal). Use this to determine which device is associated with a specific License ID.
Note: These steps only apply to Microsoft 365 for business licenses.