Can I use a gmail address to send emails using Emails & Automations?

Short answer - No.  Not if using the Emails & Automations feature in ShinePages.

You will need to use a domain-hosted business email address that you have purchased. This will look something like: yourname@yourdomain.com. You can purchase email hosting from the same place where you purchased your domain name. ie: Namecheap, GoDaddy, etc.

You can connect and verify your domain for email sending by following the instructions in the article linked below

Note:

If someone "replies" to a message sent via Campaigns or Automations - you will receive that email in your email inbox, provided to you when you purchase and set up your business email.