Any email you write in Sprout Studio can be either a "Plain" email or a "Pretty" email.
A plain email is a plain-text email and looks the same as it would look as if you were to type a personal email in Gmail, Mac OS mail or from your phone.
A pretty email is a more refined and stylized email. It has:
A header image or bar of color
The main email content
A contextually-aware button (where applicable)
There are two theming options for pretty emails:
Dark theme or light theme
Sans-serif or serif font
You can choose one of 4 options for your pretty email header:
Automatic email header, which will automatically pick the best image for the header. If you're sending the email from a gallery or from a shoot with a gallery attached to it, it'll use the cover image for that gallery. If there are multiple galleries in a shoot, you can cycle between the covers for each gallery.
Custom image, which is an image you can upload just for this specific email.
Brand email header, which will use the email header you've specified for the brand.
Brand color bar, which is a simple, minimalistic bar of color at the top of the email.
You can set up email templates to be pretty or plain. When you use that email template (for example, in a workflow, or when you manually choose it while sending an email), the configuration, content and options will be preserved.