I love that you're considering using QuickBooks! Each version of QuickBooks has a different set of features to offer business owners and I want to make sure you have all the details you need to make the switch and get going in the program.
I see that you've chosen QuickBooks Self-Employed for the product tag for this Community question. The Self-Employed version is great for one the go work and allows for you to easily sort through your business and personal finances. The important thing to keep in mind about this version of the program is that it's the most simplified version of QuickBooks and doesn't have any sort of data transfer option from other software and the import options are also limited. With this in mind, it'll take starting completely fresh in QuickBooks Self-Employed to get started with using it.
QuickBooks Online and QuickBooks Desktop do have some import options to offer which could be of use to you depending on your needs. Both of these versions of the program are designed specifically to handle business books and don't have the business-personal mix that you're looking for, so that's something to keep in mind as well.
I'd like to leave you with this page, which outlines the three products I've just mentioned so you can get a better sense of what they have to offer: All QuickBooks Products
It's important to me that you're choosing the best option for you, so don't be afraid to ask more questions. I'm here to help!
QBSE is a stand alone product. I have yet to find any 3rd party migration tool supporting it. Should you need to migrate transactions data from Quicken, consider choosing QB Online.