Hello and welcome to Apple Support Communities, granby01!
I understand you're trying to download a PDF from iCloud, but it downloads with an extension of .iCloud. I'd be happy to provide information that may help you resolve this.
Have a look at the following article for downloading data from iCloud Drive: Archive or make copies of the information you store in iCloud
"Copy files from iCloud.com
Use these steps to download files stored in iCloud Drive, or files that are accessible from iWork apps on iCloud.com:
- Sign in to iCloud.com on a Mac or PC.
- Open the iCloud Drive app.
- Find and select the file.
- Click
or choose Download Document from the Action
menu. The document downloads to your default downloads location."
If I've misunderstood your issue, please provide the following information:
- What is your operating system?
- What browser are you using to download the file?
Thank you for using Apple Support Communities.
Enjoy your day!