A warm welcome to the QuickBooks Community, Jp.
It's not possible to add more columns to your quotations within the program. However, you can still manage single and multiple rentals by creating distinct line items for each.
Furthermore, you can explore third-party applications that integrate with QuickBooks to better cater to your specific needs.
Additionally, you can refer to this article with the steps on personalizing your sales forms: Customise invoices, quotes, and sales receipts.
Should you need further assistance with your quotation in QuickBooks, feel free to reach out. I'm here to help in any way I can. Have a good one.
