Snapchat has tapped DistroKid to help build its audio library, also known as "Sounds on Snapchat".
Please note, artists are only eligible to submit their work to Snapchat if they own 100% of the publishing rights to the releases they are submitting to Snapchat. In addition, Snapchat requires that your work also be submitted to MediaNet for your music to appear in their catalogue. When uploading, make sure both Snapchat and MediaNet are selected from the list of stores you want your music to appear in.
When you submit your work to Snapchat, you will be required to acknowledge that you own the publishing rights to your work:
You can find the details of Snapchat's publishing rights grant by clicking the link at the bottom of the upload form, once you opt your release into Snapchat: