You can add contacts in three ways in Paperflite. They are:
Adding as a Distribution List
When you create a distribution list, the contacts that you add to your list get automatically added to your contacts
When you generate a link
When you generate a link either an anonymous link or a personal link, the contacts get updated in your system.
When you send mail via quick send, your contacts get updated.
A contact also gets added if a lead is generated from any of your integrations (Freshsales, Salesforce, HubSpot etc.).
You cannot have a different contact with the same email id.