You want to add hyperlinks and other HTML content to the Symantec Endpoint Protection Mobile (SEP Mobile) welcome email.
This troubleshooting step is ONLY applicable to customers that have SEP Mobile direct purchase accounts, and will not apply to those customers that have gotten their SEP Mobile accounts by virtue of having Symantec Endpoint Protection Cloud (SEP Cloud) user licenses or device licenses. Those account types cannot manage mobile and are "one size fits all."
Put another way, only customers that have login access to https://mc.sepmobile.securitycloud.symantec.com/ will be able to make the changes indicated in this article.
SEP Mobile