The option to change vendors to contractors is unavailable in QuickBooks Online (QBO). If you want to track your vendor for 1099s, we can simply open their profile and check the Track payments for 1099 box. Let me show you how:
Go to the Expenses menu and select Vendors.
Click the name of the vendors, then select Edit.
In the Additional info section, check the Track payments for 1099 box.
If you have any additional questions, feel free to add them to this thread, and I'll be more than happy to assist you. Wishing you a wonderful day ahead.