Please uninstall the WebForms M2 plugin before installing the new WebForms 3.
Execute following command to import all forms and submission from WebForms M2 after WebForms 3 is installed:
Please replace the old widget code with the new one using the Insert Widget button on CMS pages.
Use the new PHP code if you embed the form in .phtml files.
Replace the old XML code with the new XML code if you embed the form in the layout file.