If you're looking for sheet music for a specific song, the best place to start is by searching for the song title on a search engine like Google. You can also try searching for the artist name or album name if you know them. If you still can't find what you're looking for, there are a few other places you can check.
One option is to visit a site like Sheet Music Plus, which offers a wide variety of sheet music for all kinds of songs. Another option is to contact the publisher of the song directly and ask if they have any sheet music available. Finally, if you know someone who plays the song you're looking for, you could always ask them if they would be willing to share their sheet music with you.