To provide an applicant with the edit link, go to Message tab on application view and click “Send link to applicant's info” .
This message is commonly used to send responses to applicants, when they request to view all the data you are you storing on them (GDPR related right). The link containing the data includes also link(s) to edit application(s) which can still be edited.
If you do not want to send all that information (including notes etc.), go to that link, copy the edit application link(s), and send via a separate message. Please, reload the application view page, paste the link(s) to Message tab and write a message you want.