

You can use a free 3rd party tool named Link Lock by Jacob Strieb. The tool is free and ad-free, built for open source use. Password Protect Folder Using a 3rd Party Tool This is the best encryption method to lock your folder or file in iCloud. I tried all the 3rd party tools and tricks to check if there is any loophole, and I found none.

The only catch here is the folder needs to be compressed into a zip file, and then you can encrypt the zip and upload the zip to iCloud. You can directly encrypt the folder and then upload it to iCloud Drive, and when someone downloads the folder or files, they need to enter the password to unlock the folder. If you want to protect the folder content even if someone has access to the iCloud link.

It is the best encryption method available. Password Protect Folder Before Uploading to iCloud
