Functional Offhand addon

Upgrade your Bedrock offhand functionality with this addon, bringing it nearly to parity with the Java Edition! In standard Minecraft Bedrock, offhand utility is limited to shields, Totems of Undying, and a few other items that you can hold but cannot use. With the Functional Offhand addon, you can finally hold and place blocks, plant crops, place torches, use fireworks, empty water buckets, and even throw certain projectiles.

Credits: Areed-Elahi 

These changes offer a huge boost to your efficiency:

• Seamless Farming: Gather and instantly replant seeds without having to switch between your tool and your inventory every few seconds.
• Safe Building: Build sky bridges while holding a water bucket in your offhand — just in case you misstep!
• The possibilities for streamlining your gameplay are endless.

How to Quickly Equip Items

You don't need to open your inventory every time you want to swap items. You can move an item to your offhand using these methods:

• Double-Crouch: Quickly double-crouching will move your currently held item into the offhand slot. 
• Custom Keybind: Alternatively, you can set up a custom keybind for the /swap command to toggle items back and forth instantly.