On PlayStation the Helldivers DLC is sold as an entitlement, meaning that only the primary account which purchased the DLC is able to use it.
However, DLC can also be shared with other local players while in the same game or logged into the account which purchased the DLC.
When purchasing DLC on PlayStation, please note that the regions of both the game and the DLC packs need to match in order to use it. For example, you will not be able to play if you have purchased the Asian DLC bundle and are playing with the European version of the game.
If you are using the physical copy or retail version of Super Earth Ultimate Edition (SEUE), the DLC is stored on the disc. In the box should also be a code which you can redeem for the PS3 and PS Vita.