Import a contact on iCloud.com
Every contact appears on a virtual card called a vCard. You can import vCards.
Contacts can import vCard format version 3.0 or later.
In Contacts on iCloud.com, click in the sidebar, then choose Import vCard.
Select a vCard to import.
Contacts from imported vCards are added to the All Contacts group. You can add contacts to any other group by dragging them to the desired group.
If the vCard contains contact information for more than one person, each contact becomes a separate entry.
If you cannot import a vCard, this may be because it exceeds the iCloud Contacts size limit. See the Apple Support article Limits for iCloud Contacts, Calendars, Reminders, Bookmarks and Maps.