In WHMCS, billing settings are configurations that govern how invoices, payment gateways, and related financial transactions are handled within the system. Here's a step-by-step guide on how to configure billing settings in WHMCS:

1. Login to WHMCS:

   • Access your WHMCS administrator dashboard using your credentials.

2. Navigate to Billing Settings:

   • From the main menu, go to "Setup" > "General Settings".

3. Configure General Billing Settings:

   • In the "General" tab, scroll down to the "Invoice Settings" section.

   • Here, you can find various billing-related settings:

     • Auto Redirect on Checkout: Decide whether clients are automatically redirected to the invoice upon checkout.

     • Auto Redirect on Checkout with Product: Set if clients should be directed to the invoice if they only order free products/services.

     • Create Invoice on Order: Choose whether an invoice is automatically generated upon order placement.

     • One-Time Invoice Generation: Indicate if one-time invoices are automatically created for services/products.

     • Prorata Due Days: Specify the number of days before the due date for prorata invoices.

     • Prorata Overdue Days: Set the number of days before prorata invoices become overdue.

     • Send Reminder for Unpaid Invoices: Decide if reminder emails are sent for unpaid invoices.

     • Send Invoice Overdue Notices: Determine if overdue notices are sent for unpaid invoices.

     • Invoice Generation Method: Choose between "Standard" (invoices generated immediately) and "Separate" (invoices generated for each item on the order).

4. Configure Payment Gateways:

   • Go to "Setup" > "Payments" > "Payment Gateways".

   • Here, you can enable, configure, and manage payment gateways that clients can use to make payments.

5. Configure Tax Rules:

   • If applicable, go to "Setup" > "Tax Rules" to set up tax rules based on your business location and the tax regulations in your jurisdiction.

6. Save Changes:

   • After making any necessary adjustments, click "Save Changes" to apply the billing settings.

7. Testing:

   • Perform tests to ensure that invoices are generated and sent correctly, and that payment gateways are functioning as expected.

8. Regular Review:

   • Periodically review your billing settings to ensure they align with your business requirements and any changes in tax regulations.

Remember to refer to WHMCS documentation and support resources for detailed information on each of the billing settings. Additionally, always keep backups of your data and configurations to prevent any potential data loss during the setup process.