If you need codes of a specific length containing characters of a different types (uppercase, lowercase, digits, ...) you should "Generate using characterset". Codes like this are typically used for passwords and sweepstakes.
If you need codes that have a specific pattern (ie. XXX-9999-XX) you should "Generate using pattern". Codes like this are typically used for serial numbers and promotional codes.
A pattern can be defined by using the following characters:
- X = Uppercase (A, B, C, ...)
- x = Lowercase (a, b, c, ...)
- 9 = Digits (0, 1, 2, ...)
- A = Uppercase + digits (A, B, .. + 0, 1, ..)
- a = Lowercase + digits (a, b, .. + 0, 1, ..)
- # = Special characters ($, %, &, ...)
- ! = Punctuation (!, ?, ...)
- [ = Brackets ([, ], ...)
- v = Vowels (a, e, i, ...)
- c = Consonants (b, c, d, ...)
- ? = Random from all characters above
- / = Escape character