Automate Cells To Populate With Today's Date

I'm in the process of creating a budgeting spreadsheet for monthly expenses. I have one column (D) as "Paid" and column (F) as "Date Paid". Is there a formula that can automatically insert today's date of entry into the "Date Paid" column, once the "Paid" column has been filled in with an amount?

For example: I enter $20 in the "Paid" column, then the "Date Paid" column is self populated with that particular days date. I would like to do this for every sheet.