Here are two possible options: the first one uses a tabular
environment; the second column is a p{...}
column so the text will wrap; the width of this column was calculated so as to guarantee that the whole construct occupies the whole \textwidth
; you can find basic information about the tabular environment in every introductory guide to LaTeX and in the documentation of the array
package. The second solution uses a modified description
environment; the settings were made using the enumitem
package. The first solution doesn't admit page breaks; the second one, does.
\documentclass{article}
\usepackage{enumitem}
\usepackage{lipsum}% just to generate filler text for the example
\begin{document}
\newlength\Headwd
\settowidth\Headwd{Longer Text2:}
\noindent\begin{tabular}{@{}r@{:\hspace{1em}}p{\dimexpr\textwidth-1em-\Headwd\relax}@{}}
Text1 & \lipsum[2] \\
Longer Text2 & \lipsum[2] \\
\end{tabular}
\begin{description}[
before={\renewcommand\makelabel[1]{\makebox[2.5cm][l]{\hfill##1:\hspace{1em}}}},
leftmargin=*,labelsep=0pt,itemindent=-2.5cm]
\item[Text1] \lipsum[2]
\item[Longer Text2] \lipsum[2]
\end{description}
\end{document}
enumitem
package.description
environment helps?