If I understand you correctly you wish to be redirected to another page of your choosing. You will need a java redirect script for this.
Perhaps it would be better to echo out the HTML
//if statement to check if query was a success
if ($query) {
echo "<div align='center'><font color='#FF0000' face='Times new Roman, Times, serif'><strong>Email added</strong></font> </div>";
}
else
{
echo "<div align='center'><font color='#FF0000' face='Times new Roman, Times, serif'><strong>Could not add e-mail</strong></font> </div>";
}
REMEMBER single quote ' in an echo string. " will break it 😉