You have a list that needs checkboxes.
To do it for ONLY printing:
1. Select the list.
2. Click the Home tab if necessary.
3. Click the Bullets dropdown in the Paragraph group. ...
4. Choose Define New Bullet from the dropdown list.
5. In the resulting dialog box, click Symbol.
6. Choose Wingdings from the Font dropdown.
7. Select the checkbox in the first row.
8. Click OK twice.
To do for in-word checking
If you want the capability to check the checkbox within the Word document, use a content control. These controls are available on the Developer tab, which isn't visible by default. To display the Developer tab, if necessary, do the following:
1. Right-click anywhere on the ribbon's background and choose Customize The Ribbon.
2. Check the Developer item in the list to the right.
3. Click OK.
Once the Developer tab is available, you can add a checkbox content control, as follows:
1. Position the cursor where you want the first control. (Do NOT select the entire item; doing so will delete the item).
2. Click the Developer tab.
3. Click the Checkbox content control in the Controls group.
Unfortunately, you can't insert content controls to the entire group of items, as a group, similar to the way you'd add bullets.
You must insert each control individually. Selecting the checkbox content control toggles between checked and unchecked.
Don't limit checkboxes to just To Do lists - anytime you have a two-state choice, consider using a checkbox.