This setting limits the charge to 80%. It prevents the battery from staying at 100% (high voltage), which causes the battery to age faster.

HP doesn't have one single "Battery Manager" app. Instead, power management features are bundled into specific software suites:

Many of these tools allow you to adjust fan speeds to keep the battery cool, as heat is the primary enemy of lithium-ion cells. Why You Should Keep It Updated

Look under the or Utility-Tools category.

Download the HP Support Assistant from the official HP website. Run the .exe file and follow the prompts.