Song form is based on the concept that every song has been composed around a musical form or structure.   Popular song often chooses simple forms as a basis for a song but forms can be more complex as well.

A good reference on song form (structure) is the Wikipedia article,

Alive Drumming wants to provide you with the easiest and most reliable methods to describe song form and uses the term, “Song Form” for the approach that it takes in identifying and using song forms.

Song Form allows for selection using both (i) traditional names such as ’16-bar Tune’, or (ii) the  ‘stick notation’ equivalent of ‘4|4|4|4’ if that is what you prefer.

For full information on Alive Drumming’s Song Rhythm Tracks mobile app and it’s flexibility in identifying Song Forms see the page, Song Rhythm Tracks

Your options include, (i) describing just about any Song Form you are likely to want to use with “user-defined” Song Forms in the mobile app, and (ii) for popular tunes, searching for a user-contributed Song Form for that song, again within the mobile app.   There are now tens of thousands of these being shared.