Hello AngiedG,
I love that you're willing to work with your clients and what they're using or considering to manage their books. I can introduce you to QuickBooks Online and help you learn the ropes so you can have the confidence to work with the software and wow your clients. I'll go over both importing and other ways you can learn about QuickBooks Online as an accountant.
Fiat Lux has you on the right track for importing invoices into QuickBooks Online with the article Import multiple invoices at once. The great thing about this article is that it outlines how to format the file and then walks you through the import process step by step. It also includes limitations and other important details.
For a full scope of what can be imported using QuickBooks' built-in import features, I recommend checking out this article: Common questions about importing data to QuickBooks Online. It highlights what data can be imported, what order to do it in, and links on how to do it.
As an accountant working with clients, you have the opportunity to take advantage of QuickBooks Online Accountant. This version of the program sets you up with the tools and accesses needed to help your clients with their books and also includes a portal where you can do certification training on QuickBooks Online and Desktop. This is a win-win as it gives you the chance to learn the program and then if you complete the certification exams, those will show on your profile for potential clients. You can learn more about it here: QuickBooks Online Accountant
I hope this has been helpful. Please don't hesitate to let me know if you have other questions. :)
