# Using fontawesome icons

Writing my CV, I try to put symbols of email, phone, twitter, etc before the corresponding information on top of my CV. So, I basically did the following:

\documentclass[margin, 10pt]{res} % Use the res.cls style, the font size can be changed to 11pt or 12pt here
\usepackage{import}
\usepackage{helvet} % Default font is the helvetica postscript font
%\usepackage{newcent} % To change the default font to the new century schoolbook postscript font uncomment this line and comment the one above
\usepackage{fontawesome}
\setlength{\textwidth}{5.1in} % Text width of the document
\begin{document}

\mobile{+1...}

\end{document}


However, I receive the "Undefined control sequence" error. I tried to follow one of the templates but couldn't understand what causes the problem here.

Assuming you are using the res class from https://ctan.org/pkg/res. This was last updated in 2001, so I doubt it has special commands in place to insert your twitter contact. However you can simply input the icons like this:

\documentclass[margin]{res}

\usepackage{fontawesome}

\begin{document}

\faMobile\ +1...