Azure B2C Email Validation Template Customization
Azure AD B2C supports basic customization of emails sent by Azure AD B2C through Azure AD's Company Branding feature. Customization of the template is not supported at this time, though you can vote for that ask in the Azure AD B2C Feedback forum: Fully customizable verification emails
An alternative would be for you to avoid using the Reset Password policy at all and implement your own reset password mechanism which:
- Generates its own codes
- Sends its own emails
- Has its own code redemption mechanism
- Uses the Graph API to reset the user's password
Azure has update it.Now, it is available here.https://docs.microsoft.com/en-us/azure/active-directory-b2c/custom-email