Navigate to the Manage tab on the deal dashboard for the deal in question. Under the Overview section, you'll see a table of all invited LPs.
In the table, you'll be able to check their status (Viewed, Awaiting KYC). You can also click any of the headers at the top to filter the list of LPs based on who has viewed the deal, who has signed/completed, who has passed, and who has canceled their investment.
Please see this Help Center Article for additional information about how to use and send invite links.