Does anyone have suggestions on adding a vendor number for our customers? Where can you add this info into QB?

Good afternoon, @jwpratten. 

I appreciate you coming to the QuickBooks Community with your question. 

To clarify, what kind of number are you wanting to have in QB? The vendor's phone number? 

In the meantime, check out this guide as a future reference: Adding a vendor in QuickBooks Online. 

I'll be waiting for your response!