You can download your LinkedIn connections as a CSV file from your LinkedIn settings. Send this article to connectors who want to share their connections as a file.
Sign in to LinkedIn and open Settings & Privacy → Data privacy → Get a copy of your data.
Select Download larger data archive, including connections.
Select Request archive and confirm your password.
Wait for LinkedIn's email. The first email, "The first installment of your LinkedIn data archive is ready!", contains your connections. This usually takes a few minutes but can take up to 24 hours.
Download and unzip the archive, then find Connections.csv.
The file contains your connections' names, current titles and companies, and email addresses where they've shared them.
To upload it, see Import your LinkedIn connections. To upload it for a connector, see Import connections for a connector.