How can I restore a deleted contact number

For iCloud contacts, see if any of the following support articles can help:

• Use iCloud.com to restore and recover iCloud information - Apple Support
• Restore contacts stored in iCloud on iCloud.com - Apple Support
• If you accidentally deleted your calendars, bookmarks, or contacts from iCloud - Apple Support

Unlike some Android devices, contacts are neither stored locally on an iPhone nor in SIM. They are synced to an email account that you had Google, iCloud, AOL, Exchange, Outlook, Yahoo or any Other

If Contacts on iCloud, try this --> Restore contacts, calendars, bookmarks, and more using ...

Else add the email account that stores your contacts.