You may not know it, but Windows 10 has a feature that can automatically resize any open window to only take up half the screen. Thanks to it, you can easily organize the display of several windows side by side, whether you have one or two screens connected to your machine.
To automatically resize a window, grab it by the top bar, and knock it against the left or right end of your screen. A small animation, similar to a wave, is displayed. Then release the window which should be automatically resized to be displayed on the half of the screen.
On the unoccupied part, Windows should present in the form of thumbnails the windows of the different open programs. Click on any application to display it on the second part of the screen.
If two screens are configured on your PC, you will be able to display four windows of identical size, distributed on each two.
Resizing the windows will only work on the sides opposite the two screens: on the left screen, only the left end of the screen will trigger the resizing of the window, while on the right screen, only the right end will respond to the operation.