Task List/summon lv1

Legendary Pokémon are obtained through special means. Most can be "summoned" with a summon item, however, you must unlock the ability to find such shiny objects. To see which summon items you have unlocked and your progress to unlocking more, you can head over to the Summon Items page, located in the Other Links section of the Farm page.

The Wiki has more information about Summon Items and how to unlock them.