Currently the Empower Personal Dashboard does not allow for manually entering transactions into your linked or manual accounts.
If you are missing any transactions from your linked accounts, you can manually refresh your data to pull in any missing data by following the steps here: How Do I Force Data To Be Refreshed For A Specific Account.
As for exporting transactions, this is possible by following the steps in the article below:
Export Transactions To A .CSV File Through Our Web Application.