Hello, @William Lavasque. I'm here to answer your question for today.
In QuickBooks, primary admins and company admins get all access rights. If you assign the standard user role, QuickBooks lets you choose the user’s access rights. You can choose to give them all access, limited access or none.
So, to answer your question, yes you can be able to access the client data as long as that specific client give you the access or permission.
To give you more insights about the different options for user roles and access permissions, you can check out this article: User roles and access rights in QuickBooks Online.
Additionally, here's an article to guide you if you want to manage users in your QuickBooks account: Add and manage users in QuickBooks Online.
I'm just around if you have clarification or additional information with managing access to QuickBooks. Have a good one!
