To center form fields
Click the Select tool at the top of the Panel bar and select a field to be centered
Press Shift with the Select tool to select multiple form fields – they can be of different types.
Right-click and choose a command from the Center menu. Vertically places the fields midway on the page between the left and right margins. Horizontally places them midway between the top and bottom of the page. Both places them in the middle of the page.
Notes
To align only controls of the same type, you can also choose the tool you used to place those controls.
Do not edit form controls or run Form Typer on a form with active XFA controls.