If you need to add a comma after the first word in each cell in Excel using the Replicate or Substitute function, read through this article.

However, most email services and applications allow you to import addresses formatted using a comma-separated values file you export from Excel.

If you have a list of email addresses in an Excel spreadsheet, you can import this into a Mac Address Book by converting the Excel file into a text-based Comma Separated Value file.

Is there anyway I can make it so if I copy and paste those comma separated list into it excel it automatically puts each thing into different fields.