Post-it - Приложение - App Store
To "post" photos for others to see, you can create an iCloud Link . Select your photos on iCloud.com/photos , click the share icon, and choose Copy Link to send it to others.
If you are looking for the Post-it® digital app to sync notes with iCloud, it is available on the App Store . It allows you to digitize physical sticky notes and organize them across devices.
To "post" or upload files to iCloud, you can go to the iCloud Drive website . Click the Upload button in the toolbar to select files from your computer or mobile device.
If you are looking for technical "postmaster" info (like if you're a mail admin trying to fix delivery issues to @icloud.com addresses), Apple provides a Postmaster information page . You can contact their team at icloudadmin@apple.com for specific delivery problems.