LaTeX produces a main output file and at least two auxiliary files. The main output file’s name ends in either .dvi or .pdf.
.dvi ¶If LaTeX is invoked with the system command latex then it
produces a DeVice Independent file, with extension .dvi. You
can view this file with a command such as xdvi, or convert
it to a PostScript .ps file with dvips or to a
Portable Document Format .pdf file with dvipdfmx.
The contents of the file can be dumped in human-readable form with
dvitype. A vast array of other DVI utility programs are
available (https://mirror.ctan.org/dviware).
.pdf ¶If LaTeX is invoked via the system command pdflatex,
among other commands (see TeX engines), then the main output is
a Portable Document Format (PDF) file. Typically this is a
self-contained file, with all fonts and images included.
LaTeX always produces at least two additional files.
.log ¶This transcript file contains summary information such as a list of loaded packages. It also includes diagnostic messages and perhaps additional information for any errors.
.aux ¶Auxiliary information is used by LaTeX for things such as
cross references. For example, the first time that LaTeX finds a
forward reference—a cross reference to something that has not yet
appeared in the source—it will appear in the output as a doubled
question mark ??. When the referred-to spot does eventually
appear in the source then LaTeX writes its location information to
this .aux file. On the next invocation, LaTeX reads the
location information from this file and uses it to resolve the
reference, replacing the double question mark with the remembered
location.
LaTeX may produce yet more files, characterized by the filename
ending. These include a .lof file that is used to make a list of
figures, a .lot file used to make a list of tables, and a
.toc file used to make a table of contents (see Table of contents, list of figures, list of tables). A particular class may create others; the list is
open-ended.