Question

in which group can we fine the button to insert a header in the document​

Answer 1

On the Layout tab, under Page Setup, click Header & Footer. Choose from a list of standard headers or footers by going to the Header or Footer pop-up menu, and clicking the header or footer that you want.

Answer 2

Explanation:

On the Layout tab, under Page Setup, click Header & Footer. Choose from a list of standard headers or footers by going to the Header or Footer pop-up menu, and clicking the header or footer that you want.