There are many formulas to add a comma after the first word in a cell. In case you have a list arranged across a column, you can replicate the formula across the list using the Fill option.

a parser can help you create a comma-delimited file. Microsoft Excel isn't a text-parsing program, but you can use it as a parser to create tab-delimited and comma-delimited files. Open an ...

In Excel, select the cell, group of cells, or entire column that has the text you want to split. It'll need to contain two pieces of data separated by a "delimiter." This'll usually be a comma ...