Basically, you feed the lyrics into the app, then describe the song, then delete the first 20 attempts AI tries, then change genres, then keep deleting a lot of options. Or choose the first option if you're in a hurry. Some people say the songs are soulless or hollow, but if it's about the lyrics (that you wrote and didn't use Chat GPT to create), then it's cool to have an actual decent-sounding song to go with your lyrics.
Keep in mind that you give the AI song app your lyrics unless you buy a pro plan, so if you consider yourself a good lyricist, buy the monthly plan at least to retain the rights to the words. I'm sure most of the AI-generated music will eventually be deemed stolen sounds, but your words will still be yours.
Check out my song, "I Still Do." I started writing it for our 20th Anniversary but didn't get the AI boost until our 22nd. I can't sing or play instruments, but I can have a fairly professional-sounding anniversary tribute that could easily be used by others for anniversaries or wedding dances. Or even as a mega-hit on the country charts when a real recording artist sees the potential.
I know that AI music apps will ruin the jingle and Hollywood song-creation industry because it's so easy to have Gemini or Chatgpt come up with a song that captures some elements of a movie and then have that turned into a royalty-free song, but it also works for the rest of us wanting to impress our wives.