Budder is something between shatter and wax, but it’s also made using butane hash oil extraction.
What separates it is the purity: Budder has fewer cannabinoids but is richer in terpenes. Also, budder is not as solid as shatter, and it’s more wax-like which makes it much easier to use.
To use budder, put it in a bong or pipe, add it to a joint or blunt. Just like with all of the above.