Change table gridlines and colors in Keynote for iCloud
You can add horizontal or vertical gridlines between rows and columns, or add borders to cells. You can also change the color of every other row (to help the rows stand out visually), or add color to the background of all cells or only selected cells.
Add borders and gridlines
You can add horizontal or vertical gridlines to all rows or columns in a table. You can also add a border to one or more table cells.
Click a table cell or select multiple table cells.
Do any of the following:
Add gridlines to the table: Click Table at the top of the Format sidebar on the right, then below Gridlines, click the buttons to add or remove gridlines from the table body, from the header rows and columns, and from footer rows.
Add a border around the selected cells: Click Cell at the top of the Format sidebar on the right, then below Border, click the image that shows the borders you want to add. Click the pop-up menus to choose the border thickness and style; to change the color, click the color well.
To remove a border or style, click the pop-up menu and choose No Border.
Change the background of table cells
Choose the color of alternating rows
Click anywhere in the table.
Click Table at the top of the Format sidebar on the right, select the Alternating Row Color checkbox, then click the color well to select a color.