To move one existing window to another Mac desktop, open Mission Control and drag the window onto the destination Space thumbnail. You can also drag the window to the screen edge and hold it until the adjacent Space appears.
Prepare the destination
Create the destination desktop in Mission Control if it does not exist. Identify it by wallpaper, neighboring Spaces, and the windows already present. If automatic Space rearrangement is enabled, do not rely only on a remembered number.
Bring the target window into view and confirm its title or content before dragging. Similar browser or Finder windows are easy to confuse in a crowded overview.
Move only the window
In Mission Control, drag the selected window upward to the destination thumbnail and release it. Select the destination Space and confirm that the correct window arrived. The alternative edge-drag method is convenient for adjacent Spaces but less direct when many desktops exist.
Dragging a window onto a full-screen app in the Spaces bar can create Split View, which is a different result. Release on an ordinary desktop thumbnail when you want a normal resizable window.
Avoid changing the broader app rule
Dock “Assign To” settings affect an application, not just one selected window. Leave the app assignment at None when different windows from the same app belong on different desktops.
Moving a window changes its visible location. It does not rename the project, save the document, or guarantee restoration after the window closes. Record durable project context elsewhere.