You can align shapes relative to each other or to the page:

1.Hold down the CTRL key and click on the objects you want to select for alignment.

2.Click Drawing Tools/Format[Arrange] > Align and select the desired options from the menu.

Note:   If you align an object related to the page and later change the page format, you will have to re-align the object to account for the new page dimensions.

See Also

Document

Shape Alignment Options