The Cross-Device Channels section is currently a Beta option in Google Analytics, so check to see if it is available in your Analytics account first. To begin, you have to enable the option, then sufficient traffic has to flow through your Analytics so that the audience can build.
This facet of Google Analytics will illustrate cross- device information about site traffic, allowing you to make more informed device decisions in Google Ads for features such as device bid adjustments and extensions. For this section of Analytics, don’t just look at the Google Ads segment you’ve created—look at the behavior of other traffic sources and see what is working best.
For example, a lot of a site’s audience may enter your site through a mobile device but complete your conversion on a desktop device. This is typical if you have a longer conversion cycle or higher price point products. You can see the device overlap rates and what is your acquisition device, and examine this information by channel.