External (data created and sits outside Sage 300)  maybe imported into relevant sections of each Sage 300 module individually. i.e in Accounts Payable Supplier related data may be imported into different icons of this module. This can be done for Accounts receivable, General Ledger as well as other modules data. You are not able to import all the data for all the modules at the same time. It has to be done individually into each relevant module.  

You may want to contact your certified Sage 300 Business Partner for assistance.

Did you mean that data can be import using SQL Management server?

No.Not in SQL. Never bypass the Business Logic of Sage 300. Importing can be done within Sage 300 modules themselves.

Adding on to that question, is it possible to import/export csv files via Sage 300cloud?

Hello Brian

Sage 300 Cloud (Web Screens) Imports and exports are only in Excel format. In the Sage 300 Cloud (desktop) Import and Exports can be done in CSV formats.

Does Sage 300 provide any web service or API through which we can push the data to Sage 300 cloud?