How can I Backup My Phone Contact to iCloud?

See the article Back up iPhone - Apple Support

Note: If you turn on an iCloud feature (such as iCloud Photos or Contacts) in Settings > [your name] > iCloud, its information is stored in iCloud. Because the information is automatically kept up to date on all your devices, it’s not included in your iCloud backup. (See the Apple Support article What does iCloud back up?)

If contacts were saved in Mac or iPad , when the iPhone and other devices are signed in with same Apple ID and password on the same network , the contacts will sync Set up and use iCloud Contacts - Apple Support

If contacts are not in iCloud and you deleted from iPhone , they are permanently gone and can't be recovered Manage and delete contacts on your iPhone, iPad, or iPod touch - Apple Support

b-99 Said:

"How can I Backup My Phone Contact to iCloud?: I don't have any Contact in iCloud"

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Enable Contacts in iCloud Settings:

See If “Contacts” is somehow disabled.

• If it is disabled, then enable it.
• If it is enabled, then disable it and then re-enable it.