For clients who had previously accepted your invitation, you still need to initiate a request each year to "connect" their Intuit Link account to yours again.  By doing so, your client will get a TY2020 folder (or whatever you want to call it) and the TY2020 Questionnaire as well as Document Checklist will be populated for your client to complete.

If you not clear about how it works, you can follow the instructions in the "To send a Link organizer from 2020 Lacerte" section of the article below.

You should remind your client to click on the button in your invitation email (which contains a token) and use the same email address to which the invitation was sent (which should be automatically filled out when the browser is opened) when logging into Intuit Link for the first time for TY2020 instead of accessing Intuit Link directly.  This will ensure the connection is activated and avoid various other issues.

https://proconnect.intuit.com/community/tax-organizer/help/using-intuit-link-in-lacerte/00/5170