The equivalent of ⌘S when you're editing in a web app is ⌘A + ⌘C.

@natekontny the email newsletter app I was using to write today’s email.
You can add location information to your Tweets, such as your city or precise location, from the web and via third-party applications. You always have the option to delete your Tweet location history. Learn more
@natekontny the email newsletter app I was using to write today’s email.