My client sent me a portable copy of their company file so I could work on their inventory, how do I get the changes to them without them having to manually enter them?

If they have made no changes to their file while you have had it, you can make a portable copy of backup copy and send it to them.  They can restore it and be back in business.HOWEVER, if they have continued to enter transactions after they sent you the backup file, all of their data will be gone.

Original answer by @Lexiesmemere

If they have made no changes to their file while you have had it, you can make a portable copy of backup copy and send it to them.  They can restore it and be back in business.HOWEVER, if they have continued to enter transactions after they sent you the backup file, all of their data will be gone.