Hello magicianandthemu,
Welcome to the QuickBooks Community. It's essential you're able to keep track of your income and I'll be happy to show you how to do that using QuickBooks.
The program offers a versatile accounting platform that helps you streamline your accounting. If you're referring to entering invoice payments income, I encourage you to check out the following article: Record invoice payments in QuickBooks Online.
To add to the info above, here are some helpful tutorials/webinars you can reference in order to cut the learning curve for QBO. You're more than welcome to ask other questions in the comments below. I'll be one message away in case you need anything else. Otherwise, I wish you a great rest of the day.