Triggers allow tags to activate in particular situations.
We can think of the trigger as “when“: when I want to activate a certain tag.
In this way, I tell the tag to activate itself if a certain condition occurs, for example if we are on a certain page, if a transaction is made, if a video is activated etc.
Used with Variables, you have all the elements available to better track your website.
Google Tag Manager catalogs different types of triggers: Pageview, Click, User Engagement and Other.


You may also be interested by the following articles:
The value (other) in Google Analytics
Cardinality dimensions in Google Analytics
How to solve the 5 million cell limit in Google Sheets
How to track Single Page Applications with Google Tag Manager