I created a video for my client and licensed music from Adobe Stock for it. My client has asked that I send only the music track to them. Can I send them the file? If I can send the file, do I send my edited version for my client's video or the original file from Adobe?
You need to read the licencing terms to see how you can do that. Generally, you may forward licenced assets given that the customer accepts the licencing conditions.
See here for more information: Transfer license to a client - Adobe Support Community - 11990240
Look here for more information on licensing: https://community.adobe.com/t5/stock/links-for-licensing-terms/td-p/11366788
(Disclaimer: As always with licensing, this is my interpretation of the rules. I think they are correct and advice is based on reading and interpreting the licence terms and on fair use for both the buyer and the artist/stock company, but I cannot rule out that my interpretation is wrong. I'm not an Adobe employee).