To change the same value for more than one product, select the products by clicking on the checkmark field on the left. To select all products of the page, click on the checkmark field in the table header.
A counter on the left top will provide you with the information on how many products you selected. You can then change the price or the activation status. With a click on “Save changes” you will overwrite the current value by your new settings for all selected products.