I thought I read somewhere on vox complaining that there's no control of font sizes on typepad. You can, but it does require a bit of a html hack.
STEP 1: On your compose editor, click on the HTML tab.
STEP 2: Type this first: <div style="font-size: 30px;"> Where the number 30 can be larger or smaller, depending what you're feeling.
As a test, below are some random font sizes and colors and faces:
FONT SIZE 15PX
.
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PS, this post was written on my ipad, using Apple's bluetooth's keyboard (because heaven knows it's impossible to type longform on the touchscreen!)
PPS, There is a "full editor" that will allow changing font sizes and font family