NOTE: As of Windows 10 Fall Creators Update - 1709 16299.64
Microsoft has removed "Add the standard keyboard layout as a touch keyboard option" from the Typing Settings in Windows.
The tablet keyboard now remembers it's last setting and configuration options are found on the keyboard control as shown below
In tablet mode the tablet keyboard is made available from the Windows Taskbar by selecting "Show touch keyboard button"
Before Windows 10 Fall Creators Update - 1709 16299.64
The Windows 10 keyboard was originally designed for touch users on tablets, so by default the keyboard is kept to a limited set of keys than you'd find in a regular PC. This allows Microsoft to make the keyboard bigger and easier to tap the keys, but at the cost of some missing functionality -- like the Function (Fn) Keys and number keys row, and the ALT key.
To switch to full keyboard layout, you have to turn the options on in Windows Settings.
Open Windows 10 Settings from the Start menu.
Click or Tap on "Devices".
- Click or Tap on "Typing".
- Toggle "on" the setting for Add the standard keyboard layout as a touch keyboard option.
Click or Tap the keyboard icon in the task bar.
(If you don't see the icon, right-click or long-press on the taskbar and select "Show touch keyboard button.")
Click or tap the keyboard button at the bottom right of the on-screen keyboard.
Select the standard keyboard icon. It's the right-most icon.