secondary axis option not available on mac

I’m on word and I found that clicking on the inside of the chart area (I.e. where the bars/lines are, not the outside with the numbers!) and clicking the white square in the middle of the secondary vertical axis, and dragging it to the left (so that there is actually space on the right side of the graph) helped. It allows space for there to actually be an axis title on the right side of the secondary axis. Before I done this there was no option for secondary axis title from add chart element > axis titles. After shuffling it around the secondary axis title option was made available from add chart element > axis titles > secondary vertical.

I hope this helps!