You can add an entire list of email addresses to your eNewsletter Subscriptions on your blog. In this tutorial we will use Google Spreadsheet to gather the email addresses.
Go to Google Drive and create a new Spreadsheet. Add your email addresses in the first column.
Download your spreadsheet as a CSV file. (Comma Seperated Values) File > Download As > CSV
Go to your blog’s Dashboard and find Subscriptions > Add Subscribers. Upload the CSV file. Check off “Do not send confirmation emails”. Click Import. It will now create subscriptions for each of the emails in the list you created.