Soldo allows users to attach files to a transaction. They can do this via the mobile app (e.g. when a user scans a receipt) or from the Web console.
When a transaction is exported from Soldo to NetSuite, any attachments added to it will automatically be uploaded to NetSuite. See: Where can I find attachments to transactions that have been exported to NetSuite? for more on where to find these uploaded files.
Please note that files bigger than 10MB won’t be uploaded to NetSuite. The transaction itself (and any other attachments) will be exported to NetSuite and marked as exported in Soldo.