Hi there! I can definitely help you with that. Adding commas to the end of each email address manually would be a tedious task, especially with such a large list. Fortunately, there's an easy way to do this using Excel's function.

Here are the steps to add commas to the end of each email address:

1. Open your Excel file and select the column that contains your email addresses.
2. Right-click on the column and select "Format Cells".
3. In the "Number" tab, select "Custom" from the list on the left.
4. In the "Type" field, enter the following:
   
   
   Code:

   @;@,

   This will format the cells to display the email addresses with a comma at the end.
   
5. Click "OK" to close the "Format Cells" window.
6. Now, we'll use the
   Code:

   CONCATENATE

   function to add the comma to the end of each email address. In a new column, enter the following formula in the first cell:
   
   
   Code:

   =CONCATENATE(A1,",")

   This assumes that your email addresses are in column A. If they're in a different column, replace "A1" with the appropriate cell reference.
   
7. Press Enter to apply the formula to the first cell.
8. Copy the formula down to the rest of the cells in the column by clicking and dragging the small square in the bottom right corner of the cell.

That's it! You should now have a column with all of your email addresses, each followed by a comma. You can now copy and paste this column into your email blast program.