New Mac user with basic problem on MS Word

I've installed Office 365 on my new Macbook and I'm having a basic but infuriating problem. When I click on a text box/field in an existing Word document, the cursor is a 4-way arrow (the kind that allows you to move the box around). The only way I can get it to change to a normal cursor, and therefore be able to type text, is to right-click and select "edit text". Is there a way to change this default behaviour? I type in text boxes all day and it's a pain to have to keep right-clicking. With the Windows version of Word, I can click in the box and start typing immediately.