If you have more than one monitor connected to your computer, you can choose which one to use as your main display. This is the display that will show the Start menu and taskbar. It will also be where any open windows will appear when you move them to that monitor. Here’s how to make a monitor your main display in Windows 10.
First, open the Settings app by clicking the Start button and then clicking the Settings cog. In the Settings app, click System. On the left side of the System window, click Display. On the right side of the window, look for the section labeled “Select and rearrange displays.”
If you only have one monitor connected to your computer, it will be listed here as “1. Monitor.” If you have multiple monitors connected, they will be listed here as “1. Monitor,” “2. Monitor,” and so on. The number next to each monitor corresponds to its position on your desk, with the leftmost monitor being number 1 and the rightmost monitor being number 2 (or higher, if you have more than two monitors).
To make a monitor your main display, click the number next to it. A menu will appear with three options: “Make this my main display,” “Extend my desktop onto this display,” and “Duplicate my desktop on this display.”
Click “Make this my main display.” Your main display will now be the monitor you selected. The Start menu and taskbar will appear on that monitor, and any open windows will be moved to that monitor. If you have more than one monitor connected and you want to change which one is your main display, simply repeat these steps and select a different monitor.