We are trying to use WSO2 IS Rest Api for users's authentication. Is there any way to enable email otp with Rest API authentication?
WSO2 does not support REST API based MFA (Email, SMS) as of now, but it's on the roadmap.
As a community user, you may use https://github.com/wso2-extensions/identity-otp-integration-endpoints. However it is not covered under WSO2 commercial support.