Any tilde that appears in an HTML page will be translated, at the time of report publication, to the value it was assigned. If a tilde is included in the HTML that hasn't been assigned a value globally it won't be replaced; it will remain as is. However, all tildes present in an HTML file can be defined when creating a publication, so, they don't have to be globally created.
The example below shows how a tilde could be used in an HTML page.
<!DOCTYPE html>
<html>
<head>
<title>Assessment report for ~companyname~</title>
<meta name="description" content="Tilde example">
<meta name="keywords" content="Tilde example">
<meta name="robots" content="INDEX, FOLLOW">
The tildes specified above is ~companyname~ and is used in the title of the page. The benefit of this would be being able to use the same HTML page for many reports as the company name can be set when a publication is scheduled.
The value of this tilde can either be set globally and/or set at the time a publication is scheduled.
For an overview of tildes and how they can be used powerfully click here.