\documentclass[12] {article}
\begin {document}

Text alignment

\begin{flushright}
Right
\end{flushright}
\begin{center}
Center
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\begin{flushleft}
Left
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Tekst wyrównany 
LaTeX can be used as a standalone document preparation system or as an intermediate format. In the latter role, for example, it is sometimes used as part of a pipeline for translating DocBook and other XML-based formats to PDF. The typesetting system offers programmable desktop publishing features and extensive facilities for automating most aspects of typesetting and desktop publishing, including numbering and cross-referencing of tables and figures, chapter and section headings, the inclusion of graphics, page layout, indexing and bibliographies
\end {document}