Two easy methods --

1. Add the information as a document property, using File > Properties - one
of the fields on the summary tab, or create your own on the Custom tab; then
use DocProperty fields where you want the information to appear in the
document.

2. Add a bookmark for the first instance of the information (where you
actually type it), then use REF fields elsewhere. The bookmark can be a form
field.

Document properties are a bit easier if you also want to process your
documents by automation -- they're easier to read and set by VBA, and they
are retained if you output to PDF. The bookmark method puts everything in
the body of the document, which is easier to explain to others; but if
there's much editing the bookmark can be accidentally deleted.