The document’s overall class is defined with the \documentclass
command, which is normally the first command in a LaTeX source
file.
\documentclass[options]{class}
The following document class names are built into LaTeX. Many other document classes are available as separate packages (see Overview of LaTeX).
articleFor a journal article, a presentation, and miscellaneous general use.
bookFull-length books, including chapters and possibly including front matter, such as a preface, and back matter, such as an appendix (see Front/back matter).
letterMail, optionally including mailing labels (see Letters).
reportFor documents of length between an article and a book,
such as technical reports or theses, which may contain several chapters.
slidesFor slide presentations—rarely used nowadays. The
beamer package is perhaps the most prevalent replacement
(https://ctan.org/pkg/beamer). See beamer template, for a
small template for a beamer document.
Standard options are described in the next section.