Change the font size for text in the text box

You can change the font size for the entire text box by clicking the border of the text box or you can click inside the text box and select a single piece or multiple pieces of text and change the font size for the piece(s) of text.
Once the selection is over, on the Home tab, in the Font group, click the arrow in the Font Size command and select a font.

Note:
You can enter whole numbers or numbers with .5 incremental values in the Font Size command.