Is there a standard feature in NetSuite that allows vendors to create invoices? For example, they would enter the vendor center, see a PO they are associated with and create an invoice off of that PO.

You'll need to craft a Suitelet for a UI and a map/reduce script to process the transactions.

create an Invoice or a Vendor Bill?

Vendor Bill

seems like it would be pretty custom, also assuming this is regarding physical inventory do you only allow billing after they have been received? if so then they wouldn't be able to bill until its been received on your end, lastly the most common issue with people entering vendor bills that are not familiar with how they relate to PO's is that you cannot just add an item to the bill even if the same item number is on the PO as its linked at the line level, so it works off a transform from the item receipt data

Thanks for the response Israel! This would be primarily for services instead of physical inventory. Currently we are using Coupa for procurement, and they have a feature where suppliers can log into a portal and create a vendor bill. That’s where this ask originated from. It’s not necessarily a deal breaker if we don’t have this functionality in NetSuite. I was mostly curious to see if it was even possible.

ah ok, then that might make it a little easier but still custom, but it does sound like a cool feature that could be added to the vendor center