Overture allows you to send emails from your existing email address. If you have a company address that you use for correspondence you can attach this to Overture. If you do not have an address, you may wish to set one up otherwise emails will be sent using Overture's email servers, and appear as that to your recipients with your own email address as the reply address.
To begin this setup head over to your settings tab and in the sidebar locate the email settings option. This form will ask you for your SMTP settings. You may already have these settings stored somewhere when you setup your email client to receive and send emails. If not they can be found out from your ISP.
Once you have the settings to hand, simply enter them into this form. It's important to remember that these settings are added on a per user basis for example you could have email@example.com or firstname.lastname@example.org
As stated on the form if you are unsure of the Port number, leave this empty and Overture will try the default SMTP port. The same goes for the SSL checkbox, ask your email provider if this is offered otherwise do not check this box otherwise your emails will not send.
When the form is completed click Save and everything should now be setup.
If you are using Gmail or Gsuite to manage your company emails you need to make sure that you allow less secure apps to access your account. This is not because Overture is not considered secure it is simply because you need to enter your email password into the Overture settings. Head to your Sign in and Security settings in your Google Account pages.
If you need find out more about this then there is a help article on Google Support pages - https://support.google.com/accounts/answer/6010255?hl=en