Mac storage basics · Time Machine basics
Can Time Machine back up my Mac to iCloud?
Short answer: No — Time Machine backs up to a disk or a supported network location, not iCloud. iCloud syncs some data but isn't a full Mac backup.
No. Time Machine backs up to a disk — an external drive, or a network location that supports Time Machine — not to iCloud. iCloud syncs specific things (iCloud Drive, Photos, Messages and so on), but it isn't a full backup of your Mac.
For protection against losing the drive itself, combine Time Machine with a second copy kept somewhere else; see the 3-2-1 backup rule.