How to insert previous Head 1 in Footnote :WORD

Here's what I found :

How to insert a StyleRef field

There are two ways to insert a StyleRef field (or any other field):

1. Use the Insert | Field dialog (in Word 2007 and above, use Insert | Text | Quick Parts | Field...). When you open this dialog and select the StyleRef field in the "Field names" list, you will be presented with a list of all the styles currently in use in the document (see Figure 1). Just select the one you want to reference and click OK. It's that easy!

Figure 1. The Field dialog showing insertion of StyleRef field

2. Insert the field by hand. Press Ctrl+F9 to insert a pair of field delimiters (the things that look like braces but can't be entered from the keyboard). Between them, type STYLEREF and the exact name of the style you want to reference, enclosed in quotation marks. In the example shown in Figure 1, the field would be { STYLEREF "Heading 1" }.

Source : Useful StyleRef tricks