To add a Venn diagram to a Word document:
Click on the Insert tab on the top ribbon, then click on SmartArt. In the window that opens, choose Relationship, and then from the pictures available, choose the sort of Venn diagram you want, and click OK.
The dialogue box that opens allows you to type in text for each of the main circle shapes:
It doesn’t let you add text to the overlap though. If you want to add text to the overlap areas, go back to the Insert tab, and choose Shapes. Choose a shape that resembles the overlapping portion (probably an oval), and draw it and rotate it so that it sits on top of the overlap. Then right click on the oval, click Edit Text, and type the text you want.
Then right click the oval and click Format Shape; on the Fill tab click No Fill; on the Line Colour tab click No Line and then click Close.