The system uses the markup language called TxStyle to convert plain text into structured HTML markup.  When you see a merge field used as follows in an email communication:

"{{ offer_url }}":{{ offer_url }}

This creates a hyperlink - meaning, a link you can click that will direct you to a website with the address of the URL provided.  The name of the hyperlink is what is in between the quotation marks; in this case, the hyperlink is named the same as the URL link to the Offer Letter for the award.  The following is an example of an Offer Letter URL:

The applicant would click this link to bring them to their portal to accept or decline the award.

Using the same format, you can put anything in between the quotation marks to be the name of the hyperlink.  For example:

"Accept Your Award!":{{ offer_url }}

If you use only the merge field in the body of the email, and the merge field contains a URL, then the person reading the email will not be able to "click" the link.  Instead, they would need to copy and paste the link into the address box of their browser.