You can share a file with the geek within the messaging area on your dashboard.
Step 1
Visit the Purchases tab on your dashboard and click Files on the service related to the file you want to share.
Step 2
You should see a Files section open on the right. Click the blue +Add New button in that section to upload a new file.
Once the file has been uploaded, you should see it appear in the Files section.
If you click on Messages, you should also see a message was automatically sent to the worker, giving them a link to download the file.