Urchin Tracking Module UTM parameters are simply tags that you add to a URL. When someone clicks on a URL with UTM parameters, those tags are sent back to your Google Analytics (or other tracking software to track the effectiveness of online marketing campaigns across traffic sources and publishing media. The most common parameters are medium, source, campaign, term, content. However, parameters are versatile and can be customized according to what you want to track.
The biggest disadvantage of UTM parameters is the sensitivity towards an ununified system of definition (aka marketers using their own terms, lower- and upper-case letters, special symbols etc.) that might cause data fragmentation.
The UTM code itself has two components:
UTM Parameter: that starts with utm. There are 5 separate parameters you can track: utm_source, utm_campaign, utm_content, utm_term
Tracking variable: a unique variable to identify the dimension being tracked (such as the name of the traffic source). This variable is preceded by the "=" sign. You can have only numbers, letters, hyphens, '+' sign and periods in the variable.
You can use Google URL Builder tool (https://ga-dev-tools.web.app/campaign-url-builder/) to create your own parameters when you want to publish any link, and they will automatically appear on your Google Analytics