The parts of a song tend to be relatively standardized. Most of the genres that are listened to in a massive way share a structure made of a series of blocks.
This structure has remained relatively unchanged since the beginning of the 20th century and applies especially to popular music.
The parts of a song are like blocks or lego pieces that the composer can freely move, repeat and chain at will, but most songs tend to have a structure similar to this:
Intro> Verse x2> Pre chorus (bridge)> Chorus> Verse x2> Pre chorus (bridge)> Chorus> Coda
Guitar solos, ad libs, and liberties tend to apply to the second chorus and the end of the song.
In an analysis by the digital magazine Vox it was determined that more and more songs end with fade out since George Martin decided to use it in the song Strawberry Fields Forever by The Beatles.
The reason is that at the end of fading the chorus loop remains in the mind of the listener. Also, it is considered anticlimactic to cut dry.
The 5 main parts of a song
Intro
Introductory verse, with or without lyrics, that sets the tone, rhythm, and general atmosphere of the song.
The tonic chord (song base) is established and usually ends with a cadence or dominant chord.
2- Verse
After the introduction start the song with its motif. Whether sung or not, it is the beginning of construction.
3- Pre-chorus
Usually after the first verse a bridge is built that can be richer in terms of instruments or rhythms.
It tends to follow the same structure of the first verse, but it prepares the listener to enter the choir.
4- Chorus
It is the strongest part of the song, the one with the most loaded lyrics and the one that is most remembered. It is the song at its finest.
The chorus of the song is the essence of it. If the song is part of series or movie soundtracks, the chorus is the most commonly used.
5- Coda, closure or outro
It's the end of the song. Depending on how it is built and for what audience, it could sound similar to the opening verse or like the chorus.
It can end in a final chord that closes or as a fade out or fading, which is when the song does not end but loses volume.
Optionally the songs could have an instrumental section or a solo, usually with electric guitars in the case of pop or rock ballads.
It can go over the same verse structure, the bridge structure, or a completely different variation, but it always starts and links with the basic structure.
The use of ad lib ("at will" in Latin) is also common; It is when the lead singer or solo instrument breaks the traditional melody with a series of variations on the known base.
References
- Vox - Why more pop songs should end with a fade out vox.com
- Vox - Why we really really really like repetition in music vox.com
- How To Get Started With Songwriting songwritingfever.com
- Wikipedia - Song structure en.wikipedia.org
- Understanding Song Structure w / Out the Theory learneverythingabout.com
- Song Structure in Electronic Music and Dubstep subaqueousmusic.com
- How to Write a MONSTER HOOK for Every Song songwritingplanet.com