Windows — Right-click the PDF, select Open with in the drop-down menu, and click Google Chrome in the resulting pop-out list. Mac — Click the PDF once to select it, click File, select Open With in the drop-down menu, and click Google Chrome in the resulting pop-out list.
Some PDF text fields, such as checkboxes, only need to be clicked in order to input an answer.
On a Mac, you may instead have to click the “Where” box and then click a folder in the resulting menu.