Moshapin Shrine in Zelda: Tears of the Kingdom is among the ones that require Link to complete a shrine quest to access them. More specifically it belongs to the green crystal quests category.
Of all the shrine locations in TotK, the green crystal ones are really interesting because Link needs to forge his own way forward, one way or another.
As we will be going to the Eldin region to find and complete Moshapin Shrine in Zelda Tears of the Kingdom, make sure to purchase and equip the Flamebreaker armor or craft some Fireproof Elixirs.
Where to find Moshapin Shrine in Zelda: TotK

Moshapin shrine is hidden inside Lake Intenoch Cave in the Eldin region. The exact location of this cave is marked on the map, and it is to the West of Broca Island and North of Gero Pond. Its coordinates on the map are 2498, 1773, 0154.
After entering the Lake Intenoch Cave, turn right and enter a small area with breakable boulders. Use Bomb Arrows or Rock Hammers to clear the path instantly. Keep going forward until you reach a Green Crystal lying on the altar. Interacting with the Crystal starts The Lake Intenoch Cave Crystal shrine request.
How to open Moshapin Shrine in Tears of the Kingdom
The purpose of the “Lake Intenoch Cave Crystal” shrine quest is to take the Green Crystal to the position marked by the green light originating from it. Sadly, the path in this area is obstructed by non-stop lava flow.
Leave the green crystal for the time being and turn left in the cave where a Fire-Like enemy is hanging from the wall.
Defeat the Fire-Like enemy for some good rewards, and go forward to find an ancient water hydrant. Hit the water hydrant to make it active. Pick up the water hydrant and place it over the lava to solidify it into rocks, by cooling it down.
Move on to the first rock and make another rock adjacent to the last one. Keep creating the rocks from lava to make a path from one end to the other (consult the picture).

Return to the altar with the Green Crystal, and now carry it across the lava pool with the help of rocks. Keep going and you will find a shrine behind the wall of flowing lava. Place the green crystal on the Moshapin shrine platform.
This will end the “Lake Intenoch Cave Crystal” shrine quest and Moshapin shrine will appear. Interact with the shrine to activate it. Enter the shrine and receive Rauru’s Blessing.
Link has already done a great job of finding the Moshapin shrine, and the first King and Queen of Hyrule seem pretty happy with him. Interact with their statue to receive a Light of Blessing reward.