Broadly, integration in Corporate Performance Management (CPM) software refers to the capability of the system to synchronize metadata with other systems. Specifically, when new accounts or other dimensions are added to the source system, these should be instantaneously and automatically loaded into the CPM software. This is not a CSV import, but a native sync of data structures.
Scenario: Acme Corporation uses CPM software for its financial planning processes. Recently they introduced a new account called Digital Advertising Costs into their general ledger (source system).
Solution: With requirements for automated updates when new dimensions are added to the source system, this new account was immediately loaded into their CPM product. This meant that Acme Incorporated was able to start tracking and analyzing 'Digital Advertising Costs' without delay or additional manual data entry or system adjustment.
Automating metadata imports is a significant time saver and can save the users from missing data down the road. For example, imagine a new product SKU was added to the ERP, yet finance wasn't notified. They might neglect to include it in the forecast. This has been known to happen with accounts that accounting added, but forgot to tell finance. Fast forward a few months and the financial results must be re-stated. No good.
However, there are situations where new accounts or other metadata are meant to be grouped differently in the planning tool. If that is the case, confirm with the vendor that they can handle exceptions.