A utm tag allows analytics (Google Analytics) to know where your link came from so that you can attribute your events/conversions to those sources.
Google and Bing advertising automatically add (if you have it setup) the utm parameters to every url.
You would not put utm parameters on a url that is on a Printed Piece, see below.
If you don’t like the way it looks there are solutions.
URL Shorteners, standard out of the box
Redirects, allows the user to type in or click on something simple but still is going to a familiar url
https://example.com/xyz, this will redirect to https://example.com?utm_source=news4&utm_medium=email&utm_campaign=spring-summer
Hope that helps 🙂