I saw many user videos with wonderful audio background, so I would like to ask if there are sites from where I can download audio tracks for my films.

If you join the Grey Arrow Drone Club you'll find Eric Matyas' music for free, I use it all the time. All he asks is for accreditation at the beginning of your video and in your YouTube description. There are hundreds of tunes on his site.
You can also ask him to write music especially for your video. He likes drones and has written "drone themes"

Ingo Sundowner Posted at 1-21 01:49
If you join the Grey Arrow Drone Club you'll find Eric Matyas' music for free, I use it all the time. All he asks is for accreditation at the beginning of your video and in your YouTube description. There are hundreds of tunes on his site.
You can also ask him to write music especially for your video. He likes drones and has written "drone themes"

where is that group?

Some interesting...
Free Music Archive. https://freemusicarchive.org/
Bensound. https://www.bensound.com/royalty-free-music/corporate-pop
Hope it helps!

Here are some places to download royalty free music for your drone videos:

Bensound: https://www.bensound.com/
Free Music Archive: https://freemusicarchive.org/
Incompetech: https://incompetech.com/music/
Premium Beat: https://www.premiumbeat.com/
Purple Planet Music: https://www.purple-planet.com/
Storyblocks:  https://www.audioblocks.com/
Soundimage: https://soundimage.org/

Thanks all of you folks.

Yes.  Thanks to all of you!

Just a quick try to add audio.

Debugger Posted at 1-21 03:12
Just a quick try to add audio.

https://www.youtube.com/watch?v=g7tlA37YXuM

Nice flying and great job with adding audio.  Thanks for sharing.

good sharing. thx u

Hello and good day Debugger. Thank you for reaching out and for the inquiry. I hope that you will get the best recommendation from our valued DJI co pilots with regards to this matter. Thank you.

Debugger Posted at 1-21 03:12
Just a quick try to add audio.

https://www.youtube.com/watch?v=g7tlA37YXuM

Nice one!
Is crazy how much a nice piece of music can do to some drone or any footage!

Debugger Posted at 1-21 03:12
Just a quick try to add audio.

https://www.youtube.com/watch?v=g7tlA37YXuM

Great job. Just don't forgrt to give Eric the credit