On your iPhone or iPad, open Settings
Tap your name at the top
Tap iCloud
Tap Messages
Turn on Use on this iPhone or iPad if needed
Open the Messages app to view synced messages
On a Mac, open the Messages app
Sign in with the same Apple ID
Go to Messages in the menu bar
Click Settings or Preferences
Click iMessage
Enable Messages in iCloud if needed
Wait for messages to sync
On iCloud.com, messages cannot be viewed directly
Use a synced Apple device to access iCloud Messages