The Hidden Redstone Door is made up of using pufferfish in the fence. This door will open automatically as you reach closer and then close after a while.
This guide will explain to you the method to make a Hidden Redstone Door in the Minecraft Survival game.
The first thing you need to do is to place six pistons on the ground in the same way as shown in the image below.
Place smooth quartz blocks at the top of pistons. Add a redstone repeater in the middle and redstone dust on left and right side blocks. Set the redstone repeater to 2 tick delay.
Fill the gaps on the right and back side by placing smooth quartz blocks. And add a redstone torch at the top.
Place some blocks on the right side and connect the oak pressure plate with a redstone torch by using redstone dust.
The next thing you need to do is to hide the redstone. Place smooth quartz blocks on the front to make a complete wall.
Now you have to activate the door. Set the game mode to Survival to activate it. The door will open automatically as you reach closer.