B.21 Missing \begin{document}

You have put some text outside of the document environment. Check the following:

You have remembered \begin{document}
This error would be caused by, say,
\documentclass{scrartcl} ✘ This is a simple document
instead of
\documentclass{scrartcl} \begin{document}✔ This is a simple document.
You haven't placed any text before \begin{document}. For example:
\documentclass{scrartcl} This is a simple document✘ \begin{document}
instead of
\documentclass{scrartcl} \begin{document}✔ This is a simple document
You haven't missed out the backslash at the start of either \documentclass or \begin{document}
This error would be caused by, say,
✘ documentclass{scrartcl}
instead of
✔ \documentclass{scrartcl}

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