Open the Forms Module and choose Submit Button.
When you select the Submit button a window will open prompting the URL for your database. Enter the URL then press OK.
As you move the mouse cursor over the document you will see the outline of the field before it is placed.
The submit button will appear once you click the left mouse button in the appropriate place.
Click on the Submit Button option again in order to stop placing fields.
You can modify the size and location of the button while in Edit Mode. You can test the button while in View Mode.