Connect an external hard drive or SSD to your Mac
Open System Settings
Click General
Click Time Machine
Click Add Backup Disk
Select your backup drive
Click Set Up Disk
Choose whether to encrypt the backup
Wait for the first backup to complete
Keep the backup drive connected for automatic backups
To back up manually, open Time Machine and choose Back Up Now
To restore files, open Time Machine and browse previous backups
To create a full clone, use a third-party backup app
To back up important files to iCloud Drive, enable iCloud Drive in Apple ID settings
To back up important files to another cloud service, upload them to your chosen service
To keep multiple copies, store one backup locally and one backup offsite