Select the file(s) you want to send and right click

There will be a 7-zip option (if you don’t see this option please let someone in IT know)

When you expand the menu click on ‘Add to archive…’

There are a couple of things to make sure of here

Make sure you select Zip in the archive format (you should only need to do this  the first time you run 7-zip

Secondly make sure you set a strong password.  Send the password to the intended recipient separately from the attachment if they don’t already know it.

And now you have a password protected zip file. Note that you’ll be able to see the contents of the zip but won’t be able to open or extract anything without the password.