This tutorial shows how to add text boxes to your PowerPoint slide.
Select the Text tool.
Click on the slide where you want to place the text.
Click and drag down and right to create a box.
Release your mouse when the box is at the required size. 
To add text, click once in the box so you see a vertical bar – the edit icon.
Type your text.
Resize the text area by click and holding the bottom right corner, and dragging as needed.
Select the text and use standard font settings to change the text font and size.
To move the text, click and hold on an edge and clicking/dragging to the new position.