How do I insert a "click here to type box"

That box is called a content control.

First, if you don't see a Developer tab on the ribbon, right-click the ribbon and click Customize Ribbon. In the list on the right side of the dialog, click to put a check mark next to Developer, then click OK.

Click in the document where you want the control. On the Developer ribbon, click one of the two buttons that show "Aa". The one on the left is for "rich text", meaning you can apply formatting just as you would anywhere else in the document. The one on the right is for "plain text", meaning what you type will all be in the same font.

Once you've inserted the control you want, you can click the Properties button to the right of the controls and give the control a title, and set various options.