Is it possible to get custom attributes on AWS Cognito sign up form?

I was interested too, but i think is not possible using the Login Web Page hosted by Amazon cognito. I've found this information on Amazon Cognito guide: https://docs.aws.amazon.com/en_us/cognito/latest/developerguide/cognito-user-pools-app-integration.html

At the end of this document i've found:

Note

The Amazon Cognito hosted sign-in web page does not support the custom authentication flow.