Is it possible to show alert message on the page or popup window, when user SHARE the document

Question

My SharePoint Environment is SharePoint 2019 On Premise

1. Is it possible to show alert message on the page or popup window, when user SHARE the document on the Document Library.
2. When we Share the document, whether or not we could modify the mail alert template/ Content.

Thanks

Answer 1

By 'share', I assume you mean you want to show a message anytime someone edits the permissions of a document. (Since technically, I could 'share' a document by emailing someone the link to it.)

To my knowledge, the only way to achieve this would be to build a custom-code (SPFx) solution which uses API's to interact with the document's permissions granted via app-only access. And block users' ability to access those documents in the traditional way through SharePoint. This would give you full control over the UI, and prevent users from granting access (sharing) elsewhere.

Another option you might investigate is Azure Rights Management. Sensitivity labels applied to documents/libraries can be configured to automatically display headers, footers, watermarks, and even encryption when they are accessed. Exchange can also be configured to display a 'tip', when it detects users are trying to email a sensitive document. Full disclosure: I have only worked with these features in SharePoint online and I'm not certain of their capability in an on-premise environment.