The forms created or the data collected would still be accessible and will not be lost or deleted unless the same is deleted manually on your end when the account is downgraded to the Free plan. We do not have a time bound for our Free plan. However, if you do not access Zoho Forms for a year, you would receive three email notifications from our end and your free Zoho Forms account would be eligible for clean-up.

To avoid deletion of your free Zoho Forms account, we recommend you to login to Zoho Forms at least once a year and accessing other Zoho products (say Zoho CRM, etc.,) would not be considered.

If the storage limit exceeds 200 MB when the account is downgraded to the Free plan, the end users will not be able to upload files/ images to the form and submit. You will have to free-up the storage to collect files/ images from your end users. 

However, if they are just entering data to the form without uploading any files/ images, the form could be submitted with the Free plan limitation of 500 submissions/ month.