A bar code is essentially just another font that you install on your database and use to format a field on a layout for printing out bar codes. The specific bar code that you choose to use, though, could have additional requirements. One type needs to add an asterisk before and after the other text encoded and some compute a "check digit". So you'll need to research those type of details to make sure that you properly handle them as well as installing the bar code font.
And if you want to use a USB type bar code scanner with FileMaker, this thread may be of interest: Need help writing script to integrate barcode scanning
And I've been playing around with scanning Bar codes into FileMaker GO on my iPhone. That uses different methods than those discussed in the above thread, but can work pretty well as long as you stay within the limits of what the device's camera can do.