On dual monitors, programs usually remember the last screen on which they were closed and retain an affinity for such.
Use the Win+[right or left arrow] key combination (or the Win-Shift+[right or left arrow]) to move a window without dragging.
If, during your current session, wherein you might open multiple windows of a particular application, open the first new window, restore down, move it to the other monitor and then close it. Each and every time you open a new window in that application, for the duration of that session, every new window will open in the other monitor.
There is no way I know of to get a particular application to open on a particular monitor each and every time on the initial run of the application.
I do know that when I open explorer and move it to another monitor, then close it, it will always open on that same monitor. Same with Windows update, Resource Monitor, AutoCad Architecture, Word, Excel, Notepad ++ and many others.
However, Disk Management, Task Scheduler, Services, etc.. always open on the primary monitor no matter which monitor I had them on upon closing.