Double checkmark symbol

Rather than \checkmark from the amssymb package this symbols looks closure to \checked from wasysym. You can use:

\documentclass{article}
\usepackage{xcolor}
\usepackage{wasysym}

\newcommand\doublecheck{\textcolor{blue}{\checked\kern-0.6em\checked}}

\begin{document}

    \doublecheck

\end{document}

to produce:

Just for fun (meaning that @Andrew's answer is the one that should be accepted): a TikZy proposal.

\documentclass{article}
\usepackage{tikz}
\tikzset{pics/.cd, 
checkmark/.style={code={% starting point : https://tex.stackexchange.com/a/132790/121799
\pgfgettransformentries{\tmpxx}{\tmp}{\tmp}{\tmp}{\tmp}{\tmp}
\draw[line width=\tmpxx*1pt,blue!80,fill=blue!60,line join=bevel] (0,.35) -- (.25,0) to[bend left=5] (0.8,.6) to[bend
right=5] (.25,.18) -- cycle;}}}
\newcommand{\doubleckmark}{\begin{tikzpicture}[baseline={(0,0)}]
\path (0,0) pic[scale=0.4]{checkmark} (0.12,0) pic[scale=0.4]{checkmark};
\end{tikzpicture}}
\begin{document}
\begin{tikzpicture}
\pic{checkmark};
\end{tikzpicture}

abc \doubleckmark\ xyz  

\end{document}