When you create LinkedIn campaigns with a CSV file as a source for your leads, please consider the following information:
Closely supports only CSV format
the file size should not exceed 2MB
the mandatory fields for the CSV file for the LinkedIn campaign are: First Name, Last Name, and LinkedIn link. A header for each column is obligatory.
The mandatory fields for the CSV for the multichannel campaign are: Email, LinkedIn URL, First Name, and Last Name. You can use the screenshot below as a reference:
