To automatically advance by a month in Excel, you can use the EDATE function. This function returns a date that is a given number of months before or after a start date. For example, if the start date is in January, and you use EDATE to add two months, the return value is in March.

To use the EDATE function:

1. Select the cell where you want the new date to appear.
2. Type =EDATE(
3. Click the cell that contains the start date.
4. Type a comma (,)
5. Type the number of months that you want to add or subtract.
6. ) and press Enter.