Select the Insert tab on the ribbon. On the Insert tab in the Text group click Date Time. Position the cursor where you want to insert the formula.
On the Insert tab in the Text group select the Quick Parts drop-down list and the click on Field.
For stopping this changing you need to add to the cell reference and change the relative reference to absolute reference. Microsoft Word for Windows 2016 2013 2010 or 2007 1. Press CtrlC on a Mac press CommandC. Go to Insert tab.