Texinfo files start with at least three lines that provide Info and TeX with necessary information. These are the ```\input texinfo``` line, the `@settitle` line, and the `@setfilename` line. If you want to run TeX on just a part of the Texinfo File, you must write the `@settitle` and `@setfilename` lines between start-of-header and end-of-header lines.

Thus, the beginning of a Texinfo file looks like this:

```\input texinfo   @c -*-texinfo-*-
@setfilename sample.info
@settitle Sample Document
```

or else like this:

```\input texinfo   @c -*-texinfo-*-