The Builder's Wand allows you to place multiple blocks at once.
Using it on a block will place more of that block on the block you clicked on, including to adjacent blocks. Naturally, this will use them up from your inventory.
While holding the Builder's Wand, it will render a wireframe at all the locations that blocks will be placed.
It can place up to 9 blocks at once, based on the blocks closest to the one you're looking at.
There is also a Creative Builder's Wand that does the same, but has no recipe and can break up to 49 blocks instead.
Configuration
The max amount of blocks broken is set via the item's excessive_utilities:amount_blocks Data Component, rather than a config option.
For example, /give @s excessive_utilities:builders_wand[excessive_utilities:amount_blocks=9999] would give you a Builder's Wand that can place up to 9999 blocks at once.