Hi Liz_VC,
Based on your description, you would like to add conditional formatting in the Excel workbook. When dates in Column H is less than today, highlighting them, otherwise making checkboxes in Column I checked. I would like to follow the steps below to add conditional formatting:
1. Go to Home> Styles> Conditional Formatting, click New Rule.
2. Create a new rule as follows.
This article about using a formula to apply conditional formatting is for your reference.
3. In this case, you can mark checkboxes whose following dates are not highlighted. You can refer to this article to add check boxes in Excel.
Regards,
Yoga