Quick answer: Tap the spinning record in the bottom-right of the TikTok. The sound page often names the song and artist. If it only says "original sound", use Shazam or save the MP3 and identify it.
1. The sound page
Tap the round spinning record on the right side of the video. If the creator used a song from TikTok's library, the sound page shows the title and artist, and often a link to play it on a streaming app.
2. Shazam or the Control Center button
Play the TikTok out loud and open Shazam. On iPhone you can add Music Recognition to Control Center and identify songs without opening an app. On Android, the Google search widget has a music note button that does the same.
3. Hum, whistle or play it to Google
In the Google app, tap the microphone and say "what's this song", then hum for 10 to 15 seconds. It is surprisingly good, even with a bad voice.
4. Read the comments
Someone has almost always asked "song?" already. Sort by top comments or search inside the comments for "song" or "sound".
5. Save the MP3 and identify it
When the video has talking over the music, save the audio with the TikTok to MP3 converter. Then play the MP3 to Shazam in a quiet room, or skip to a part without voices. This also helps you keep a snippet you love while you look for the full track.
"Original sound" problems
"Original sound – username" means the creator recorded their own audio, or re-uploaded a song as their own sound. Tap it anyway: the most-used video is often the first upload, and its caption may name the song.
Sped-up and slowed versions
Sped-up and nightcore edits change the pitch, so Shazam can miss them. Try identifying a clip of the original speed: search the lyrics you can make out in quotes on Google, plus the word "lyrics".