This method will guide you to enable Developer tab in the Word Ribbon, and then insert an ActiveX control of Option button in Word. Please do as follows:

1. Click File > Options to open the Word Options dialog box.

2. In the Word Options dialog box, (1) click Customize Ribbon in left bar, (2) check the Developer option in the right box, and (3) click the OK button. See screenshot:

Now the Developer tab is added in the Word Ribbon.

3. Go ahead to click Developer > Legacy Tools > Option Button. See screenshot:

4. Now a radio button is inserted in the document where your cursor places on. Right click it, and select OptionButton Object > Edit from the context menu. See screenshot:

5. Now the option button name is editable. Please type the texts you need to replace it.

6. For inserting multiple option buttons, please repeat above Step 3 - 5 as you need.

7. Exit the Design mode with clicking Developer > Design Mode. See screenshot:

Now these inserted option buttons are checkable.

Besides the above method, would you like to know another easy way in quickly inserting radio button in Word document? Now, Kutools for Word’s Radio Button utility can help you quickly insert multiple option buttons in bulk. Please do as follows:

1. Please select the text that you want to insert radio button for, and click Kutools > Check Box > Radio Button. See screenshot:

Now, the radio button is inserted.

2. Exit the Design mode with clicking Developer > Design Mode. (Note: Click to view ways about showing Developer tab in Word Ribbon.)

Tip: Kutools for Word also supports to quickly insert checkbox (content control), checkbox of ActiveX Control, or Checkbox (form field) with one click.