Step 3: Click on Symbol and choose the box character to replace the character. Step 2: Select Define New Bullet from the menu. Step 1: Select the Home menu and choose the Bullets button. Step 4: Copy and paste the checkbox at the line of text needed. Step 3: Change the default X to others and make changes to the checkboxes. Step 2: Go to Developer and select the Check Box Content Control at the beginning of the first line. Insert Checkbox In Word Document On Windows Method 1: Developer Tab How to Add Developer Tab in Microsoft Word.