As it was mentioned, when it comes to online resources,
Google Books and
archive.org provide you with scanned critical versions (at least those that are legally available today), but when it comes really to digital text, the Latin text itself converted to the electronic form, as it has been mentioned, both websites as
perseus.tufts.edu and
thelatinlibrary.com (+thousands others smaller webs that provide random famous Latin works, Wiki Source etc.) - albeit, as every modern text
(by modern I mean accessible to a lay person pretty much since the invention of the book print, I don't mean scrolls and papyri etc,) they themselves come
ALSO from a conversion of some critical edition and, aside from the fact that we don't know which one and don't have the apparatus criticus, perhaps the more serious problem with it is that those texts are converted by amateurs which means that they contain mistakes and sometimes you don't know whether it is a mistake caused by the conversion or whether it is "a kind/type of mistake" that would be present in the critical edition as a part of some form of reconstruction. The problem is the amateurs typically don't transcribe it by hand, but they use various picture-reading software to create texts from PDFs, scans of book and such, which often induces errors. Then they often go over the text one more time at least to correct for some obvious mistake, but it is a difficult task for one person who does it in their free time to make a flawless transcription.
There is, however, at least one more alternative when it comes to TRANSCRIBED (digital) text and that is
PHI LATIN TEXTS.
And now I realized I made this post once already into the "Grammar tips section" and how come it hasn't been linked already :-/
THREAD: reliable-digitized-latin-texts-on-the-internet-how-to-perform-a-corpus-search