It very much depends on the authors, with some simply namedropping the sources, others going to the point of accurately quoting and referencing books and chapters, and some others going the full length.

The anonymous author of the Lazarillo de Tormes, written ca. 1550, pseudo-quotes the Holy Scripture time and time again, but never to the point of individuating chapters and verses. He also quotes Pliny and Cicero, but in general terms, though the quotations he uses are rather well known: "no hay libro por malo que sea que no tenga alguna cosa buena" (there is no book, bad as it may be, that doesn't have something good), and "la honra cría las artes" (honour raises the arts). Bear in mind that this is a short novel, scholarly as it may be, so the necessity of accurate citations is not there.

More scholarly works, like the edition of Alfonso X's "Las siete partidas" by Gregorio López is full of explanatory notes, and notes containing references for good. I will pick something at random from the Partida Primera. In Law XII, he adds a footnote "d", where you can find this very precise comment:

Et licet Principis auctoritas ,seu confirmatio statuti interueniat, vniuerfitas qua fecit statutum,posset collegialiter contrauenire inconsulto Principe, secundum Abbatem,in cap. dilecto colum.2, .de prebendis. Et praedictis adde quod habetur in Curijs de Valladolid. Anno domini 1537, petitione 28.

Gonzalo Fernández de Oviedo, the great naturalist, cites an absolutely inordinate amount of sources when writing his "General and Natural History of the Indies", always referencing book and chapter of any of his sources, though frequently forgetting to mention the titles of the book he is quoting:

The Abulensis says (book III, chapter LXXIX) about Eusebius (Of the times) that there were three Athlanteans: one of Archadia, another of Mauritania (that we vulgarly call Morocco), and that Hesperus was a brother of this second one,and that both went to Africa, to the Occidental part, in the land of Morocco, and that one of them held the cape of Africa against Occident, and the other held the neighbouring isles, that are called Fortunate and that the poets call Hesperides, named after Hesperus. But I thing that El Tostado fooled himself in thinking that the poets called Hesperides to the Fortunate isles or Canary, and neither did historians, because Solinus (De mirabilibus mundi, chapter LXVIII) says these words: Ultra Gorgades Hesperidum insulae sunt, sicut Sebosus afirmat, dierum quadraginta navigatione in intimos maris sinus

Outisde the Renaissance period, about a century later, we find authors that go far beyond this, like the royal prosecutor Agustín del Hierro in the cause against the Duke of Híjar for treason and conspiracy, where he inserts a torrent of absolutely precisecitations into the text, to the point of the text becoming quite unwieldy. I leave his accusation linked here.

https://books.google.es/books/ucm?vid=UCM5319445866

There was not a monolithic culture, and neither was a common style of citation, with different practices depending on the authors, some opting for footnotes, some going with detailed quotes duly referenced, some just namedropping, etc. Anything can be found, at least in the case of Spanish scholarship.

A lot here does depend on the author and the time period, but here's an example from a text I'm intimately familiar with. My expertise is in the 13th century, specifically regarding theological texts, and I edited one (the Ad instructionem of Simon de Hinton, written in the mid-13th century as a Dominican training text). I made an edition of this work for my PhD. Here's a short passage from it to show how Simon cited other works:

Unde sequitur, “Neque adores, neque ea colas,” quasi dicat non facies ea ad adorandum et colendum. Nunc autem non adoramus imagines, sed refertur honor et adoratio eius ad imaginatum, scilicet ad Deum,vel ad sanctum cuius est imago, ut dicit Augustinus, libro tertio De doctrina Christiana. Sequitur, “Non adorabis, neque coles.” Inter que sic distingue, “Non adorabis,” scilicet veneratione corporis, ut inclinando eis vel genuflectendo, “neque coles,” scilicet affectione mentis. Unde Glossa, “aliud est colere, aliud adorare.” Potest quis invitus adorare vel adulando regibus idolatris, vel tormentis victus, cum sciat idolum nihil esse. Colere vero est toto mentis affectu et studio mancipari. “Ego enim” discretive quasi dicat nullus alius, “sum dominus,” et ideo timendus, “Deus tuus,” et ideo diligendus. “Fortis zelotes,” id est diligens amator, Deut. 5, “Deus tuus Deus emulator reddens iniquitates patrum,” scilicet non custodientium precepta data, “in filios,” id est puniam etiam ipsos filios, si patres non custodierint ista precepta.

You'll notice here that de Hinton cites Augustine specifically by work and book, and includes quotations. There's also a reference to the bibilical book of Deutoronomy.

Here's another:
Quare ergo ex hoc vino non mixto. sicut ex illo vino mixto, cum eiusdem speciei sint, confici non possit non video. Videtur tamen decretum quoddam, De consec. dist. 2. velle contrarium, ubi Apparatus dicit quod secundum aliquorum opinionem non fit consecratio.

Here, one of the glosses on the Decretum is being cited.

And then there's this one:

Alia opinio, cui magis credere possum, ponit quod aqua transit in sanguinem sed tamen prius est a vino absorbtaEt ita verum est quodammodo quod aqua non transit in sanguinem, scilicet immediate, quia non transit nisi prius sit absorbta a vino et quasi facta vinum; et sic non contradicit priori opinioni.

Here, de Hinton does not cite a specific source for "alia opinio", but I was able to track down its probable origin in a work by the contemporary theologian Robert Fishacre.

So as you can probably see, within the same document you have very detailed citations, more general ones, and ones where the author is not cited as well. They're not footnotes per se, but they are definitely references. It should be pointed out that for de Hinton, the more recent the source, the less likely it is to have a detailed reference (not surprising, as works by contemporaries like Albertus Magnus and Robert Fishacre were not yet in wide circulation).

Hope this helps with a practical example from the 13th century.