To pay the ULEZ (Ultra Low Emission Zone) charge, you need to follow these steps:

1. Visit the official Transport for London (TfL) ULEZ payment website or use the TfL "Pay to Drive in London" app, both of which offer a user-friendly way to pay.
2. Enter your vehicle registration number to check if your vehicle needs to pay the charge.
3. Confirm your vehicle’s ULEZ charge status and select the date(s) you want to pay for.
4. Pay the daily charge of £12.50 (for most vehicles) using accepted payment methods such as credit/debit card online or via the app.
5. You can pay up to midnight three days after driving in the zone.
6. For frequent travel, you can set up an Auto Pay account, which automatically deducts charges monthly to avoid missing payments.

If you prefer, you can also pay by phone using the TfL contact number and provide your vehicle details and payment information. It's important to keep your payment confirmation for your records. This process ensures you avoid penalties and support compliance with ULEZ rules in London.