How do I shorten the width of my broadcast email?

Hello,

I understand I can shorten the width of my broadcast email by using an html block. I don’t know html so can anyone paste in the code I would need to use? Is the standard width of a text block in Infusionsoft 100pixels? I would want to start testing by starting at say 65 pixels. I am using Google Chrome if that matters.

Thanks,
Wendy (for Jim Otis)