How to automatically notify an employee about new documents?

I have the first employee who creates a Work Order, and, after clicking the Start button, creates a Stock Entry.
And there is a second employee who must issue the goods and make a Submit Stock Entry.

Is it possible to somehow configure ERPNEXT so that the second employee, having logged into the system, receives notifications about the documents that he must Submit?

Have you looked into the Email Notification functionality? This allows you to create email notifications based on document triggers.

Alternatively, what if employee 1 would assign the Work Order to employee 2? This will create a ToDo and also issue a notification email…

I thought that when an employee logs on to the system, he sees the documents that he needs to submit, but perhaps an email notification will do

maybe can do something like a dashboard - when an employee logs in, he sees a list of documents with red circles and the number of documents?

You could also achieve this with a report I guess that will filter for this user the documents to work on… Have you looked into script reports?