There's no better way to ensure authenticity and accuracy than by starting with your own writing as source material. This article describes how to upload writing samples to your account.
Navigate to your Content area.
From your home screen, click the Content option on the left side menu.
Option: Upload individual file(s)
Click the Upload button in the upper right portion of the screen and select the Upload files option.
Select the file(s) you wish to add to your account and proceed.
Your files will appear in the Content section when they have finished uploading.
Option: Bulk content upload
From Google Drive:
From Microsoft Sharepoint:
From Windows:
From Mac:
Click the Upload button in the upper right portion of the screen and select the Import content option.
Select the ZIP folder containing the contents you wish to upload and proceed.
Your files will appear in the Content section when they have finished uploading and unzipping.