Hello and welcome,
In my case (I use direct payout, so I only take a commission, and let users settle the remainder of the payment afterwards), I am fine with with PDF Invoices & Packing Slips for WooCommerce (free version).
At first I thought it was not working so I reach the support, and they help me out understand how it works. You can actually issue the invoice at various stages (statuses) of the order (as shown below). As my invoice was still in “processing” status, the invoice was not issued (yet).
And it relies completely on WooCommerce.
On another project, I have very special requirements (I thought it was impossible actually to solve), but they sorted it out with some code.
But I had to buy the pro version for this code to work.
Here is how it looks like within HivePress :
I had to address a small glitch though, the button “invoice” was also appearing when the vendor was looking at customers’ orders (customers get charged, not vendors*). Even if you clicked on the button, there was an error message, so the vendor could not access it anyway.
All I had to do was hide the button with CSS.
Note : Vendors also get charged as I use “Paid Listings”, but HivePress provides another page for these orders (and the invoice button works also fine, and customers don’t have access to it).
Cheers !