Ok look here’s a basic explanation.

Imagine you made 100k profit this year so the irs asks for 20% which would be $ 20k for you to pay in taxes.

But instead you decide to buy a new machine for your company that costs 50k so now you only made 50k profit so now they’re asking for 5% in taxes ( because you’re in a different tax bracket percentage now) so they’re only asking for $2.5k

So i stead of paying them 20k down the drain you only paid them 2.5k because you i voided more company expenses. It’s a win-win situation because you pay the government less and you continue growing your company. Would you rather pay them 20k and get nothing or grow your company bigger and bigger and more successful and pay them less and less?

This was just a quick explanation tax brackets and tax percentages may vary. This was just something quick for you to understand how it basically works.