Hi there, Becky.
 
Yes, you can set up a customer who is also a supplier in QuickBooks Online (QBO). You may use a distinct character on the Display name as since the system won't accept identical names for a customer, vendor, and employee.
 
Example:
 
- Customer: Angel SmithC
 - Vendor: Angel SmithV
 
 
I've added these screenshots for your visual references.


 
For additional resources about adding customers or vendors in QBO, you can check out these articles:
 
 
Aside from that, you can also get more tips while handling your customer or vendor transactions through these links:
 
 
Please let me know how else I can help you with setting up your customer or supplier in QBO. I'm more than happy to provide additional assistance. Keep safe!