Select all of the data you want to format and head to the Home tab. Click the Format as Table drop-down arrow and pick an alternating row style. Confirm the cell range for the table data and click "OK." You'll then have your data formatted as a table with an alternating row style.

By using this method, alternate row or column shading is automatically applied when you add rows and columns. Here's how: Select the range of cells that you want to format. Go to Home > Format as Table. Pick a table style that has alternate row shading.

Select Use a formula to determine which cells to format. Type the formula Select the format of your choice. Click OK. The MOD (ROW (),2)=0 function will highlight every 2nd row starting from the first. Select the first highlighted row then hold the CTRL key and select the other highlighted rows.