Your song is yours. On a paid plan, when you finish a track, you receive a license covering the sounds you used in it, along with a document listing exactly what's cleared. This license allows you to release music built on those sounds commercially — on streaming platforms, social media, and beyond.
However, a few things fall outside that license, which are your responsibility:
Lyrics you write
Any vocals or voices you record or add
Make sure you have the right to use them — don't use someone else's voice, recording, or words without permission. As long as what you bring is yours to use, you're free to release and share your music.