Hello abacus3247,
Managing your transactions has never been easier with QuickBooks Online. With the amazing features offered by the program, you can simplify the way you handle your transactions. I'll be happy to steer you in the right direction with this so you can focus on the things you enjoy doing.
Making sure you're recording and matching your transactions properly is an essential step for maintaining clean books. Based on what you've described, I encourage you to check out this helpful article which shows you how to properly: Categorize and match online bank transactions in QuickBooks Online. For linking a deposit to an invoice, check out this article here: How to link a deposit to an invoice.
If you still have questions after checking out these articles, feel free to leave a comment below. I'll be here to assist.