A. some heading: Text
B. another heading: more Text
C. yet another head: lots of Tex
I tried:
\begin{description}[\Alph] %[font=$\Alph\ $\itshape]
\item[some heading] Text
\end{description}
A. some heading: Text
B. another heading: more Text
C. yet another head: lots of Tex
I tried:
\begin{description}[\Alph] %[font=$\Alph\ $\itshape]
\item[some heading] Text
\end{description}
I'm not sure whether the numbers in Head1, Head2, ... were supposed to be actual numbers or just example of headers, as in first header, second header, and so on.

\documentclass{article}
\usepackage{enumitem}
\newcounter{itemalph}
\setcounter{itemalph}{1}
\newcommand\xitem[1]{%
\item[\Alph{itemalph}.~#1:]
\stepcounter{itemalph}
}
\begin{document}
\begin{description}[font=\normalfont\itshape]
\xitem{Head1} description
\xitem{Head2} description
\xitem{Head3} description
\end{description}
\end{document}
\Alph{itemalph}. creates A. and so on (the dot is there for that purpose), ~ is a non breakable and flexible space and #1 is the argument of \xitem. So \xitem{Head1} will produce A. Head1: and so on.
– Alenanno
Sep 09 '16 at 17:47
I define an enumdescription environment which does the job:
\documentclass{article}
\usepackage{enumitem}
\usepackage{etoolbox}
\newcounter{enumdescr}
\makeatletter
\newenvironment{enumdescription}{%
\setcounter{enumdescr}{0}%
\pretocmd{\descriptionlabel}{\refstepcounter{enumdescr}\enit@format\Alph{enumdescr}.~}{}{}
\apptocmd{\descriptionlabel}{:}{}{}
\setlist[description]{font=\normalfont\itshape}
\description}%
{\enddescription}
\makeatother
\begin{document}
\begin{enumdescription}
\item[Head1] description
\item[Head2] description
\item[Head3] description
\end{enumdescription}
\end{document}
This snippet should work:
\documentclass{article}
\begin{document}
\begin{description}
\item[A. Head1:] Text
\item[B. Head2:] Text
\end{description}
\end{document}
enumerateis much better thandescriptionhere...It looks like you're usingenumitemalready... – Sep 09 '16 at 17:06itemize,descriptionis not numbered. It can be faked, but most timesenumerateis easier, in my opinion -- but you were quickly choosing another answer before clearifying the question such that others had a chance to improve their post ;-) – Sep 09 '16 at 17:15enumerate@ChristianHupfer – Dr.PB Sep 09 '16 at 17:19enumerate- based answer, that's why I deleted my answer. – Sep 09 '16 at 17:28