- /give <player> shulker_box
Gives the named player a new Shulker Box item.

- /give <player> shulker_shell
Gives the named player a Shulker Shell item.

- /give <player> shulker_box:<number from 0 to 16>
Gives the named player a new colored Shulker Box item

The config file allows you to configure how the plugin should behave,
such as allowing named mobs to drop Shulker Shells or Shulker Boxes.

The permission nodes can also be changed to your liking in the config file.
(The give command uses the " minecraft.command.give" permission node already).

https://stakdek12.github.io/Shulkers/