By default, Microsoft PowerPoint resizes text as you type so that it fits into a placeholder. For example, if you type a bulleted list and put in more text than will fit in the placeholder, PowerPoint reduces the font size and line spacing until all the text fits (with 8 points being the minimum font size). For title text, if a few words bump to a second line, the text is reduced by one font size so that it fits on a single line.
Text AutoFit will also reduce text to fit inside a placeholder that you make smaller, and it will enlarge the text again if you then make the placeholder larger.
You can turn text AutoFit on and off. When it is on, you can adjust how it functions within a given placeholder by using the AutoFit Options button 
, which appears near your text the first time it is resized. The button, when clicked, displays a menu giving you options for dealing with the overspilling text. You can stop resizing text for the current placeholder while still keeping your global AutoFit setting on. You can also display the AutoCorrect dialog box and turn off the AutoFit settings altogether, so no text will resize automatically. For a single-column slide layout, when text spills out of a placeholder, you also get these options: to split the text between two slides, to create a new, blank slide with the same slide title, or to create a two-column layout on the original slide. You get these options whether AutoFit is on or not.
The text AutoFit setting for body text also applies to notes you type into the notes pane.
AutoShapes
AutoShapes such as callout balloons and block arrows lend themselves to text messages. When you type text into an AutoShape, the text is attached to the shape and moves or rotates with the shape.
Text boxes
Use text boxes to place text anywhere on a slide, such as outside a text placeholder. For example, you can add a caption to a picture by creating a text box and positioning it near the picture. Also, a text box is handy if you want to add text to an AutoShape, but you don't want the text to attach to the shape. A text box can have a border, fill, shadow, or three-dimensional (3-D) effect, and you can change its shape.
WordArt
Use WordArt for fancy text effects. WordArt can stretch, skew, curve, and rotate your text or make it 3-D or vertical.