Which App can be used to take orders directly from distributors or Retailers using a link sent to them by a company? This app should also integrate itself easily with quickbooks so that it updates the system on sales automatically?
Are thinking of something like a simple order form page that's accessible from a private link? Or are you thinking more along the lines of a public-facing "order now" button on a browsable page that lives on your website, allowing distributors to place orders freely?
QuickBooks is meant to be more of a back-of-house system that integrates all your sales, orders and expense channels. As such apps (and their interfaces) are what handle the kind of distribution you're interested in. If you use systems like PayPal and Square, you'd handle sales/orders through the 3rd party system and then sync those transactions with QuickBooks.
There are some robust inventory tools I've heard other community members mention, like SOS Inventory, but their usefulness might depend on how you've already organized and want to handle your distribution.
Hope this helps start the conversation. Are you using QuickBooks Online?