First, Word has "documents", Excel has "spreadsheets", and Gridlines are
set at the Worksheet level. If you want finer control, borders are provided.

Joy wrote:

I do not want to use border. I want to show or hide gridlines instead. I
went to Page Layout and chose Show/Hide Gridlines, only after I had selected
my cells I wanted to change and it changes the whole document and not just
those cells selected. What am I doing wrong? Thanks anyone!