Now I am more confused.
The screen shot that you posted was for a form and the checkbox for "HTML (Limited) box is checked" is n a form - which means that you are talking about viewing a record.
Are you saying that the dashboard issue is not relevant as you are really just asking how to make a link on a record and those record(s) just happen to be listed on a report on your dashboard..
if so, let's dumb this down.
Make a URL formula field with your link.
"
https://apps.irs.gov/app/eos"
set the field properties to open in a new window.