When the right margin is reached (or the \n character is met) a line
break occurs and text continues from the left margin. Upon method exit,
the current position is left just at the end of the text.
It is possible to put a link on the text.
Example:
Begin with regular font
$pdf->setFont('Arial', '', 14);
$pdf->write(5, 'Visit ');
Then put a blue underlined link
$pdf->setTextColor(0, 0, 255);
$pdf->setFont('', 'U');
$pdf->write(5, 'www.fpdf.org', 'http://www.fpdf.org');