Understanding what the Key Field is
In a contacts import via .CSV file, the key field will be used to uniquely identify each row.
It ensures that each row in the table is unique and can be identified separately from all other rows. This will allow you to update your contacts or add more in the future.
Important: The app will merge duplicate contacts for the selected key field. If, for example, you want to have multiple contacts with the same phone number, your key field should be a different value (email, ID, etc.).
Choose one that will never change, i.e: phone number, VAT ID, full name...
If you are not sure which could be your Key field, the App can generate a random ID for you (but keep in mind that this .CSV cannot be updated later)