When promoting an ad across multiple channels, it is important to consider the different ways to collect data. Tagging, being one of the aspects of collecting data is important. When using URLs tagging is required for the ads. URLs themselves can be edited with URL builder. During the process of adding fields to the URL, you will want to think about the fields that you want in it. The fields that are essential are Campaign source, Campaign Medium, Campaign term, Campaign content, and Campaign name.
Google analytics looks at the site that you just came form to figure out the the source. Whether the user is coming from a referral or a paid search, google uses the categories called source and medium to see where the user has originated from. This is where URL builder comes in. Instead of naming the traffic the way google does by default, you have the choice of different parameters. Google has its own way of classifying these parameters also. Using URL builder, various parameters, and tags is the best to see what channels are being used.
https://www.bounteous.com/insights/2017/09/19/campaign-links-in-google-analytics/?ns=l