Can QB on-line record customer/ supplier number? how?

What kind of business do you run? SaaS or else?

Hi there, @frosales-rtacs-n.

I hope you’re having a wonderful day. Let me share some insight about creating duplicates in QuickBooks Online.

When you add another customer, vendor, or employee, you'll get an error message when you use a duplicate name and that you need to enter a different one. Though, it would be awesome to have the option to add a number to your lists. Rest assured that I'll relay this message to our team in concern here on my end and add your vote for this one.

I recommend sharing your thoughts and ideas through your account. Our product development team reviews all the feedback we receive to ensure we’re meeting the needs of our customers. 
 

Here's how:
 

1. Select the Gear icon at the top, then Feedback.
   
2. Enter your comments or product suggestions then select Next.
3. You'll be provided a list of suggested Help articles related to your comment. You can read through them or select Skip and send message.
4. From the drop-down, choose the appropriate category, then select Send message.

Drop me a comment below if you have any other questions about printing forms in QuickBooks Online. I'll be more than happy to help. Wishing you a good one.