Glad to see you in the Community @GeneSAWINpro.
Let me share some information regarding the number of customers, vendors, and employees you can add to QuickBooks Online.
There is no actual limit for these types of data you can enter into your QuickBooks Online account. However, it may affect the software's performance if you have tens of thousands of customers, vendors, or employees. The more data you have in QBO, the longer it may take for the program to open pages. Please check out this article for more details: Why is my QuickBooks Online slow?
Just in case you want to know the features available per subscription plan, you can check out the QuickBooks Online Plans and Pricing link: https://quickbooks.intuit.com/pricing/.
If you have other questions in mind, feel free to comment below. Have a great day ahead!
