How to upload ads.txt to your website (quick checklist)
Where to place the file, which URL must work, and how to verify quickly.
1) The file must be accessible at: https://YOURDOMAIN.com/ads.txt
2) It must not be placed in a subfolder. Not /files/ads.txt, not /public/ads.txt — only /ads.txt.
3) Serve it as plain text when possible (Content-Type: text/plain).
4) After uploading, test in a browser and also re-check with this tool.
5) If you use caching/CDN, purge cache after updating ads.txt.
Tip: Your hosting panel usually has a File Manager where you can upload ads.txt to the web root (public_html).