Welcome Emails?

Just wondering if anyone has any good advice on what to include in a welcome e-mail.

My app is business model is that the app is free for companies with less than 5 users, so I'm not sure what kind of call to action that I can include.

I'm a technical founder, so marketing is not my forte. Right now my welcome e-mail basically reads "Welcome to the app. Please enjoy."

Anyone have any thoughts or links that might be worth reading?

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