Email Templates Urls/Hyperlinks

Email Templates Urls/Hyperlinks

I am trying to update my email template when sending out invoices so that there's multiple URL links within the email.
I see when sending an email I can insert a URL, but that just adds the url as text and doesn't provide me to name the link, so the email body just prints the URL. 
When trying to edit a template the icon for images and URLS also disappear. I tried using HTML coding like so: 
 <a href="SITE URL">SITE NAME</a>
the just prints out the text, as it doesn't seem to accept HTML coding.
How can I add Hyperlinks in my template?