Adding Multiple Subforms to a Single Form

Adding Multiple Subforms to a Single Form

I'm writing to ask what the terms were on including multiple subforms in a single form? 

It is unclear which subscriptions include the ability to add multiple subforms (between Basic, Standard, Professional, and Premium). Anyone have a clear answer on this? 

Below is the error message I'm seeing while on the 'Trial' version of Zoho Forms.

Thank you!