All Paperform plans come with unlimited storage for your form data while your account is active (you haven't cancelled or suspended your account), however each plan comes with a timeframe for how long your submission data will be stored. This doesn't effect your forms, they will all remain in your account until you delete them if your account is active, it just effects your submission data (results). Here are the time frames:
Paperform Essentials: Uploads storage for 6 months
Paperform Pro & Agency: Uploads storage for 18 months
All your submission data can be downloaded as a CSV or Excel file.
You can also connect Paperform with over 1000 Apps using Zapier to take your data elsewhere.