How does one scan a QR code in the first place?
And what do the damned things DO anyway?
In some smartphones, support for scanning QR codes might be built into the stock camera app. As that is not the case with the Cosmo, you'd need to download an app. There are lots to chose from, some of which may be heavily infested with advertising. Some of the apps has lots of extra features, such as being able to do a web search for the contents of a code. That might be useful if one would scan a barcode in a shop and would like to look for information online.
Personally, I usually just want to know what's in a code. Should there be anything to look up, I prefer to do so myself. Currently I am using the VintaSoft Barcode Scanner, because (1) it's available on Google Play, and is, thus, somewhat vetted by Google, whatever that means, (2) VintaSoft is in the barcode scanning (and creation) business, so they seem likely to know what they're doing, (3) it's free and (4) it's ad free. It has very few "extra" features. It does, however, identify (which means I don't have to tell it what kind of code it is) and read many sorts of barcodes and similar (you may have to enable some of the more obscure ones in the settings, should you want to read those). There is also the VintaSoft Barcode Generator, should you want to create QR/barcodes/etc of your own.
As to what QR codes and similar does, they're a simple way of printing machine readable information on paper, or showing it on a screen. The stripey ones you find in shops (EAN codes) typically just represents a bunch of digits, such as an article number, that the cash register can look up in a database and thus get the price (I'm simplifying a bit here). As those only carries information in the horizontal direction, they're called 1D codes (as in one dimensional).
Codes made of dots, such as QR (Quick Read, by the way), Data Matrix, Aztec code etc, are often called 2D codes. These can contain significantly more information. 2D codes are often used to represent text or numbers, so anything you could say with text, you could say with a 2D code. On principle, each dot, bright or dark, could be one bit, a one or a zero, but to make 2D Codes more robust to damage and read errors, the actual coding of information into a dot pattern, is rather complicated, and exactly how much information fits into a code of a given size (number of dots) depends on how much error correction information is required for any particular application.
While entirely possible to just store a snippet of plain text in a 2D code, usually they're used for things like a web address, which may be easier to scan than to type, or maybe a bit of encrypted data. While you can scan such codes too, the contents will typically just be a string of apparent nonsense, unless you can also decrypt the information, which is a different topic. Examples of 2D codes with encrypted data in them are digital postage stamps (usually based on Data Matrix) or some train tickets (usually based on Aztec code).
As an example, this is a QR Code containing the URL for this forum thread:
Would you like to read more, here's a link to the Wikipedia article on QR Codes:
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