Can't Save Link Without localhost — What's the Correct URL Format?

My code reviewer asked me to add a link under the “Flex Accounting” workspace to the newly created web page. I added the link using this URL:
http://127.0.0.1:8007/finance_form

However, he said I shouldn’t include http://127.0.0.1:8007 in the URL.

When I replaced it with just //finance_form, I got a save error (as shown in the screenshot).

Question:
What’s the correct way to link the page without using http://127.0.0.1:8007 and without causing a save error?