A family of Microsoft relational database management systems designed for ease of use.
You can also consider using the SDK and developer toolkit for QuickBooks.
This (IMHO) works a whole lot better then say some kind of ODBC connection (which is usually read only anyway).
We used the QuickBooks SDK, wrote the code in .net (vb.net), and then we call/consume that .net code from VBA.
The result is we are able to push (create, and send) invoices from ms-Access directly into QuickBooks, and do so without having to do some "manual" export and then some import into QB.
So, a simple click of a button sends and creates a whole invoice from Access directly into QB.
And since a invoice in QB allows one to set/create a sales rep, which in effect is a employee?
Well, then we have code to add sales reps (employees), and we thus also have code to add a new company from Access to QB.
So, adding a invoice to QB from Access also required the ability to add companies and employees to QB, and then add invoices. All this occurs directly from Access without any intermediate steps.
You can find the SDK here:
https://developer.intuit.com/app/developer/qbdesktop/docs/get-started/download-and-install-the-sdk
As noted elsewhere in answers here, the SDK does require rather solid developer skills to use.