When a user makes a UI gesture that your app perceives as a signal to start dragging data, a drag and drop operation begins. The app responds by informing the system that a drag-and-drop action is about to begin. The system communicates with your app to obtain an image of the data being dragged (a drag shadow).
The fundamental drag and drop sequence is as follows: Move the pointer to the object. To "capture" the object, press and hold the button on the mouse or other pointing device. Move the pointer to the appropriate location and "drag" the object there.
To drag from My Files, do the following:
Use your mouse to navigate to a folder in My Files after you've launched Phone screen in the Your Phone app.
Press and hold the file for a long time until a checkmark appears, then let go.
Long press the file(s) you've selected again with your mouse, and a thumbnail will display.
Choose the text you'd like to move.
Without clicking, move the mouse pointer anywhere on the selected text.
Hold the left mouse button down until the insertion point turns into a white arrow pointing up to the left.
Drag the selected text to the new spot with the left mouse button.
The object is "dragged" in this manner. After you've moved the object to the desired location, raise up the mouse button to "drop" the thing into its new location. You can choose an object on a touchscreen device by just touching it with your finger.