Welcome to the Community. In QuickBooks Online, your Profit and Loss report is not saved as a separate file on your computer unless you export it. Instead, it stays within the QuickBooks platform.
When you click Save As next to the Customize button while viewing the report, it is added to your Custom reports list. To access it, go to Reports in the left navigation bar and select Custom reports.
If you would like to download a copy of the report as a spreadsheet on your computer, you can export it. You can also visit this link to personalize your reports in QuickBooks Online.

Before we wrap up, I suggest you explore QuickBooks Live Expert Assisted to streamline your accounting, maintain precise financial records, and access professional support. This could free up valuable time, allowing you to concentrate on expanding your business.
We'll provide ongoing assistance if you have any further concerns.