DateTime::createFromFormat is not working

I am trying to use the DateTime::createFromFormat
I got a error message as - Fatal error: Class ‘PHPMaker2020\xxxx\DateTime’ not found in C:\wamp\www\

Your post is not clear enough. In which part of your PHPMaker project did you write that code? In addition, please post your code for more discussion.

You may try \DateTime, see Using namespaces: Basics:
https://www.php.net/manual/en/language.namespaces.basics.php