Good day!

I have a pure php code, so my table was in echo and I want to change the font and font-size of text in table header but when I put thid code:
PHP Code:
echo "<font size="18" face='Arial'>";
echo 
"<table>";

and 
at the lower part i close it
echo "</table>";
echo 
"</font>"
It only take effect in the text outside the table. and when I try to put it on the <table> It doesn't take effect.

Thank you in advance