Typically, the ending of a Cinderella story features Cinderella and the prince in a joyous moment. There could be fireworks, music, and everyone around them celebrating. It's all about the ultimate happily-ever-after with no more hardships for Cinderella.
The ending scene is really charming. Cinderella finally gets her happily-ever-after with the prince, and there's a sense of celebration and joy. The visuals and music make it even more enchanting.
I'd suggest looking on platforms that offer royalty-free music. However, getting the specific MP3 you want for free might be tricky as it could infringe on copyright laws.
It could be a variety of songs. Maybe it was a custom-written piece for the movie or a popular track that fit the mood. Without knowing more specific details, it's hard to pinpoint exactly which one.