Trying to find Hokers in Hollow Knight: Silksong is part of the Flexile Spines quest you get from the Seamstress in her balloon in the Far Fields area. It's also kind of urgent, as you're basically trapped in the areas near her until you do, since she crafts you the item you need to use on the wind pillars to float your way out of the hole.
You need to gather 25 Spine Cores from these creatures, but unlike gathering the pilgrim shawls for Bone Bottom, these items don't simply drop from killing them—there's a special trick to farming the item. All that said, here's where to find Hokers and how to gather Spine Cores in Silksong.
Hollow Knight: Silksong Hokers location
To find Hokers, you need to go right from the Seamstress's balloon into the next area—the first one is above the initial platform you come to. These monsters are essentially floating faces that fire out spikes in different directions if you hit them, but you need to do more than kill them to actually get the 25 Spine Cores for the Flexile Spines quest. What you need to do is:
Jump up and hit a Hoker once so it fires out its spikesHit the spikes where they're embedded into the floor or wallThis will turn them into a collectible "Spine Core" itemRinse and repeat until the Hoker is dead. Depending on its position and where it fires the spikes, you can usually get quite a few per monster. Once that first one is dead, keep heading right until you find the next. There are a couple of Hokers you can farm in that room to the right of the Seamstress, so once they're depleted, simply leave and return to respawn them until you have 25 altogether.
When you're done, bring them back to the Seamstress and she'll craft you the Drifter's Cloak so you can use the wind pillars to escape Far Fields.