This guide will let you know how to do Duplication Glitch 1.17.34 in Minecraft Bedrock Edition. You have to follow the step-by-step instructions in this guide to do so.
You can do the Duplication Glitch 1.17.34 in Minecraft Bedrock Edition very easily. You can duplicate all the items in your world and apply the same method in other platforms, i.e., Minecraft PE, PS4, Xbox, Windows 10 editions, irrespective of playing on the mobile, iPad, and other devices.
The items you need to do this glitch are Cobblestone, Water Bucket, Chest, and Oak Sign. 
As you can see in the image below, you have to build three blocks upwards in the U shape and extend one of the sides for one step.
After that, break the two middle blocks from the ground and then place the chest there. There will be a space between the chest and the third block, as shown in the image below.
You will need to place the Oak Signs to the extended side of the block. Furthermore, place the water between the blocks with the help of the water bucket. Now you are ready to duplicate the items. 
It is recommended to do this glitch in creative mode. You can duplicate nine items at the same time. Now you need to take your player’s position, as you can see in the image below.
After that, you have to come to the Pause option and click on the Save & Quit option.
Now again, go to your world, grab the item, and go inside of the water. Place the item in the chest, and you will see all the bubbles are going down. After putting the item, you will take the damage of two hearts, and then you will exit out of the game by pressing the Alt and F4 button or X buttons.
If you are playing the game on the console, you will need to go back to the home screen and close the application as soon as possible.
Now exit the game. When you come back to the game, you will find your item gets doubled.