Click the Options tab.
Next to Link Appearance, check Highlight
URLs or Do not Highlight URL.
Note: URL is the acronym for Uniform Resource Locator (the Web
page address).
Click Save. A message appears informing you that your options have been updated.
If you selected Highlight URLs, Web addresses in your mail will be blue-underlined. When the recipient clicks the link, it takes them to that Web page.
If you selected Do not Highlight URL, all Web addresses in your mail will appear as normal text and are not active. Clicking the Web address does nothing.