Finder: Sync files with iCloud – check System Preferences iCloud ‘on’ so files are backed up to ‘cloud storage’
Finder: iCloud – view online see where files are stored remotely (www.icloud.com)
Finder: Sync files to OneDrive – see where files are stored, both in Finder locally and remotely (www.onedrive.com)
Finder: Sync files to other cloud storage e.g. Dropbox – see where files are stored, both in Finder locally and remotely (www.dropbox.com)
Apple Photos app: iCloud view online (www.icloud.com Photos), edit and share photo files
Only store sensitive data on the cloud if it is a system protected by two factor authentication, like One Drive, or Google Drive.