I would like to create Cognito (using CLOUDFORMATION) which allow login with Username & Email, I have gone through AWS user pool documents and also follow Cognito Doc, But didn't find any solution.

I would like to create Cognito (using CLOUDFORMATION) which allow login with Username & Email, I have gone through AWS user pool documents and also follow Cognito Doc, But didn't find any solution.

You can check here the cloudformation for a Userpool: link
About your question:
Use "AliasAttributes" with an array with the string "email", "preferred_username"
yaml:
AliasAttributes:
json:
"AliasAttributes": ["email", "preferred_username"]
edit: AliasAttributes instead of UsernameAttributes