My laptop battery never charges to 100% and it stays on 99

You need to calibrate your battery and sensors. Unplug and run the laptop until the machine shuts down for "critical low battery", then leave it turned off while it charges back up. One, two, or at most three cycles like this will let Ubuntu calibrate how much power is available at what sensor readings, and should cause the display to more closely reflect what you expect.

If your battery is removable, remove it, disconnect AC power, and hold down the power button for 15 seconds. This will reset the power manager. Reconnect all power and see if the problem is resolved.

If your battery is not removable, then disconnect AC power, leave the computer turned on and not sleeping/hibernating, and let the battery drain to zero. Once the computer turns off, hold down the power button for 15 seconds. Reconnect the AC power. Turn computer back on and let it recharge the battery, and recheck operation.

If the above two options don't resolve the problem, and you dual-boot with Windows, boot into Windows, and locate the power/battery settings. Look for an option that allows you to tailor the battery charge... something like it'll charge to 98% and identify that as full... it might be in the power or energy saver or "ECO" settings. Reboot into Ubuntu and see if the problem is solved.