Board Thread:Support Requests - Getting Technical/@comment-26229189-20151023134123/@comment-4731443-20151023182838

You don't need to be an admin if the page is not protected, but you should have the community's approval before changing templates. Since you are new to this, I would recommend testing your changes in a subpage to avoid breaking templates that are in use in article pages. For example, when editing Template:Infobox, you could create a copy at Template:Infobox/dev and make your edits there until you are satisfied with the result.

As for changing the functionality of a template, that's a rather broad topic, so I'll refer you to help pages such as:
 * Help:Template
 * Help:Template parameters
 * Help:Parser functions
 * Help:Infobox

If you have more specific questions, several users here will be happy to help.