I hear your sentiments, @User74. The option to delete multiple line items in an invoice at once is unavailable in QuickBooks Online.
I recommend submitting your recommendations to our Product Development Team. They take customer's feedback seriously when planning future updates and improvements to QuickBooks. To do that, here's how:
- Go to the Gear icon.
- Under Profile, select Feedback.

- Enter your suggestions and click Next.
After saving your invoices and sending them to your customer, you can record the payment to link it to the invoice and balance your accounts.
Don't hesitate to ask if you have additional questions about managing your invoices, User. We want to ensure everything is taken care of. Keep safe.