Spreadsheet conditions

[Elizabeth_Garcia2470]

I have a spreadsheet that I am tracking bills on. One of my columns indicates whether or not a bill has been paid for that month. I would like the date of payment to change (separate column) to a month ahead, when yes is designated in the paid for that month column. For example, yes is marked as previously paid and I would like the date to automatically update from Feb 8 to Mar 3 (and continue to update each month).  How do I do this? 

I have searched everywhere and watched multiple videos, but nothing shows how to do this specifically. Any help you could provide is greatly appreciated. 

[#2]

@Elizabeth_Garcia2470 

Could you attach a small sample workbook demonstrating the problem (without sensitive data), or if that is not possible, make it available through OneDrive, Google Drive, Dropbox or similar?

[#3]

@Elizabeth_Garcia2470 

In addition to providing a copy (without confidential or private information) as requested by @Hans Vogelaar , although it may be clear once we see the actual arrangement of data, could you describe your objectives in creating this spreadsheet.

Is it solely a matter of knowing whether or not a bill has been paid (Y/N and date) OR are you tracking more in a budgetary sense, ultimately wanting to know expenses for utilities, food, etc., by month. Do you also track checks written outside of the context of a bill? And so forth?