what means 1000 submission per month?

Hi,

The 1,000 monthly submissions means that you can receive up to 1,000 submissions per month, regardless if it is from only one user or not.

Please visit this link, to provide you more information: https://www.jotform.com/help/408-Understanding-Your-Account-Usage-and-Limits

Hi,

Submission per month means it is the maximum submission limit your account can receive.
To know more details please refer to the guides.

Understanding Your Account Usage and Limits
Account Pricing and Monthly Limitations