Hello, @accounting-emint. Allow me to answer your questions about A/P Aging Summary Report customization in QuickBooks Online (QBO).
Regarding your first question, the answer is yes. You can modify the A/P Aging Report, but the available options are limited. As for your second question, there isn't a feature that allows for the removal of the current row display or alteration of the 1-30 range to 0-30 as it is determined by calendar days.
Furthermore, if you want pull up more detailed report, you can use A/P Aging Detail Report.
If you wish to share your custom reports to other members of your team, refer to this guide: Manage and share custom reports in QuickBooks Online Accountant.
You're always welcome to comment in this thread if you have additional questions about customizing A/P Aging Summary Report or any other concerns inside QBO. We're always here to help. Have a good one.