There is an error showing on my entry When you use Accounts Receivable (Debtors), you must choose a customer in the Name field.

Welcome to the Community, @accounts-aceline. I'd be more than happy to share some information about working with journal entries.
 

Your NAME column and its associated field are used for assigning customers, vendors, and employees to the record when creating entries. The use of this is optional. If you need to create an entry without using it, you can.

When connecting customers/vendors/employees to a journal entry can affect your reports, it depends on what you enter.

To identify what you may need to enter in your NAME ▼ drop-down menu when reclassifying prepaid expenses through journal entries, you'll want to contact an accounting professional. If you need assistance finding one, there's an awesome tool on our website called Find an Accountant. Each ProAdvisor listed there is QuickBooks-certified and able to provide helpful insights for driving your business's success.

Additionally, you run and customize the Journal report. This helps you view all your created entries in QuickBooks. Just click the Reports menu, then type in Journal in the search bar. 

Drop a comment if you have additional concerns related to journal entries. We'll be sure to get back to you. Take care.