Hi Priya,
P21 Enterprise is not necessary to prepare a regulatory submission, but it sure makes the task easier.
Community will help you validate your data (including against define.xml) to comply with FDA and PMDA requirements. It will also help you generate a define.xml from an Excel template that you’ll need to complete by hand. However, Community does not create analysis result metadata (ARM) nor does it help you with creating a Reviewer’s Guide. These and many other productivity tools are only found in Enterprise, which is why many organizations, including FDA and PMDA, prefer Enterprise.
You can request a demo at https://www.pinnacle21.com/ to help you better understand the differences.
Best,
Max