Automatically delete files from Downloads folder and temporary files

1. Go to Settings > System > Storage.
2. Toggle on the Storage Sense feature.
3. Click Change how we free up space.
4. Check Delete files in my Downloads folder that haven't changed for over 30 days and Delete temporary files that my apps aren't using. You can also check Delete files that have been in the recycle bin for over 30 days.

One important point to note: not all files in the downloads folder will be deleted after 30 days, just those that haven't changed in the past 30 days. This means if you download a file and open it daily without making any changes to it, it will still be deleted after the 30 day mark. If you turn this setting on, you should move anything out of the downloads folder that you intend to keep.