To access the Customer Center in QuickBooks, open the software and navigate to the main menu. Click on "Customers" or "Sales" depending on your QuickBooks version. Look for an option like "Customer Center" or "Customers & Receivables" and click on it. This will open the Customer Center where you can manage customer information, view transactions, and perform tasks like creating invoices or recording payments. For further guidance or if you encounter any issues accessing the Customer Center, contact QuickBooks Support at ?1-855-200-0590. Their representatives can assist with navigation or troubleshooting specific to your software version.