We recommend ProtonMail a secure email service based in Switzerland.  When used as a stand alone app it can almost replicate the SMS experience with the security of encrypted email.

https://proton.me/business/healthcare

Alternate HIPAA compliant email providers that provide a signed BAA.   We recommend choosing 1 provider and using it solely for answering service use.  Doing so allows unique notifications and sounds to be setup so you know when its an answering service email.  Alternatively by only using one email provider solely for answering service messages will help to ensure interruptions from spam or other sources.

Hushmail – https://www.hushmail.com/plans/healthcare-hipaa-compliant-email/

Egress – https://www.egress.com/blog/compliance/how-we-help-you-comply-hipaa

Mail Hippo – https://www.mailhippo.com/

Secure My Email – https://www.securemyemail.com/hipaa-compliant-email

Virtru – https://www.virtru.com/hipaa-compliant-email/

Paubox – https://www.paubox.com/

Google Workspace ( email ) https://support.google.com/a/answer/3407054?hl=en , https://workspace.google.com/products/gmail/

Outlook / Office 365 – https://www.microsoft.com/en-us/industry/health/microsoft-cloud-for-healthcare

Zoho Mail – ****Please note we do not currently recommend Zoho for any of their products.  Their support is atrocious and their products never work without support.  https://www.zoho.com/mail/hipaa.html