Plan details includes name of the current plan, plan expiration info, count of all the created documents (Invoice, Estimate, Purchase Order, Credit Note), Items and Clients.
If you have just subscribed to a new plan from Professional Invoicing website then that plan will get auto-synced with Professional Invoicing app (iOS/Android/Mac) but if that plan is not getting auto-synced/reflected on your iOS/Android/Mac app (user account) then this article is for you.
If your current plan is expired or you are getting plan limitations alert message (Clients limitation) then you need Buy / Subscribe / Renew plan from Professional Invoicing website.