Luckily, there is an option to turn the tablet mode off.

If you don't want to use tablet mode or are not familiar with it, you might find this function annoying or face difficulties while using your computer. If you have a 2-in-1 device, Windows 10 will by default startup as Tablet Mode. Windows 10 comes with a dedicated Tablet Mode, which you can find in your Notification panel on the bottom right of your taskbar or in Settings by searching Tablet Mode.