 To apply borders to cells select the cells of interest and then go up into the home font area find the border drop-down and select the option you want. I'm going to select all borders here which will surround each cell with a thin line. I'm going to select the same area go back this time select thick outside border and that applies a thick border around the outside. You can really get customized by going to the more border and select different pattern lines as well as different colors. To remove cell borders select the cells go back and click on no borders.