I can't find the e-invoicing section in Settings. Where is it?

The E-invoicing (ZATCA) section and the E-Invoicing Guide tab only appear for a company that is registered for VAT, because e-invoicing only applies to registered companies.

1. Open General Settings → Settings → Tax & E-Invoicing.
2. Turn on «The company is VAT-registered» at the top of the tab.
3. The VAT number and VAT rate fields, the e-invoicing section and its guide tab appear at once.
4. Enter your VAT number (15 digits), then turn e-invoicing on as described in «How do I enable e-invoicing and the QR code?».

While e-invoicing is on, the VAT-registration switch cannot be turned off.