Generating bar codes can be as simple as choosing an online service, selecting which type of bar code to use, entering the text to encode, clicking submit and saving the result. Although the process is simple, each of the steps involves a number of considerations. For example, an online service works well for generating a few bar codes, but could prove problematic for a large number of them. In that case, downloadable software might be a better option.
When preparing to generate bar codes for a particular need, you should consider the options available and match them to your needs. If you are in manufacturing and need bar codes for items headed to a retail store, one dimensional, or 1D Universal Product Codes may fit the need. If, however, you don't need to worry about interoperability issues or can't afford the overhead of using UPC codes, there are other options.
Quick Response, or QR codes, are 2D bar codes capable of encoding much more information. The codes themselves are free to use, flexible in size and easy to generate. If you decide that QR codes are what you need, the decision to use static or dynamic codes still remains. A static code pointing to your Facebook page is easy to generate and print on flyers or other marketing material. The URL to that page is encoded into the QR code, creating a permanent one-time link between the two.
If you need more flexibility, dynamic QR codes are available. To use a dynamic QR code, you need to encode a URL for a site that allows you to transparently redirect to another page on the web. In this way, you can go back and change where the end-user lands without having to regenerate the QR code.