All information about the respective license and a text for Copy&Paste can be found for each song in the download window. Example:
Cinematic Suspense Series Episode 004 by Sascha Ende
Link: https://filmmusic.io/song/5798-cinematic-suspense-series-episode-004
License: https://filmmusic.io/standard-license
If you use two songs in your project, you have to do a copyright attribution twice, even if it is the same artist, here's an example:
Cinematic Suspense Series Episode 004 by Sascha Ende
Link: https://filmmusic.io/song/5798-cinematic-suspense-series-episode-004
License: https://filmmusic.io/standard-license4bit Games by Sascha Ende
Link: https://filmmusic.io/song/5800-4bit-games
License: https://filmmusic.io/standard-license