Backup

Here's how to set up iCloud https://support.apple.com/en-us/HT208681

Take care: iCloud is a sync service. If you want to make a real backup of your MacBook, you have to use TimeMachine and an external drive

Here's how to use TimeMachine https://support.apple.com/en-us/HT201250

Reading the answers of Sterling r and léonie in this thread can give you useful information https://discussions.apple.com/thread/250088757

It’s strongly recommended to use TimeMachine to make backups.

If you want a cloud backup service, try one of the ones in the article below.

Cloud Backup Services - Best (2)