Mission Skills are part of Crew Skills consist of four sub professions. These skills are used to send your Companion characters on on various missions to recover information, hunt down loot, or complete other goals to bring you rewards:

The Mission Skills are:

Diplomacy

Investigation

Treasure Hunting

Underworld Trading

When you use a mission skill, you’ll select a companion, choose a mission from an ever-changing pool, and send that companion out after the prize. Player can choose to use any or all of their three Crew Skill slots for mission skills.