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.

How to Separate Text From Numbers in Excel. When you open a raw data file in Excel, the program doesn't always recognize the way in which the data is formatted, such as comma-delimited, tab ...

For Excel to divide the values, however, the cell must contain a delimiter, a character that specifies where the first number ends and the second one begins.