Social Booth uses Sendgrid for email delivery.  You will need to signup here. It's free for 200 emails/day. If you need more there's a plan for $10/month that gives you 40k emails/month.

1.       Enable Email

Checking this will enable the email sharing button for users to email their photos.

2.       Sendgrid Username

This is the username that you signed up for Sendgrid with.

3.       Sendgrid Password

This is the password for your Sendgrid account.

4.       From Email

This is the email address that you want the emails to come from when they are sent to the users.

5.       Email Subject

The subject of the sent email.

6.       Email Message

The body of the email message sent to the user. You can use some basic HTML like <b>, <i> etc.