Add package for adding watermarks

letter.tex

@@ -4,6 +4,9 @@
 \usepackage{tikz}
 \usepackage{tikzpagenodes}
 \usepackage{hyperref}
+\usepackage[nostamp]{draftwatermark}%
+\SetWatermarkText{Draft}
+\SetWatermarkScale{8}
 
 \signature{\vspace{-1.5cm}NAME HERE}
 \address{\vspace{2cm} \\ Computer \& Information Sciences \\ University of Strathclyde \\ Livingstone Tower \\ 26 Richmond Street \\ Glasgow \\ G1 1XH}