When you scan a card in Covve Scan, you have the option to add the card details as a new contact on your phone. Simply open a card you already scanned, tap on the contact icon (bottom right) -> Save to contacts -> right below the New contact -> tap on the drop-down arrow -> and select account to save it.
For iPhone users, this will open the iPhone new contact dialog, and when you tap Done it will create a new contact on your phone. In case you have multiple contacts accounts on your phone (e.g. iCloud, Outlook, Google Contacts, etc.), and you want to save this card in a specific account, please make sure that you set that account as the default contacts account on your phone. To do this, go to your iPhone Settings -> Contacts -> Default Account
For Android users, this will open a dialog with all the available Contact Accounts on your phone, and you can select in which account you'd like the contact to be saved.