In order to sell cryptocurrencies on the OKX exchange using GEO Pay, you need:

1. Log in to your OKX account
2. In the top menu, click on the Buy cryptocurrency button
3. Click on the button Buy using a card or Payment of third-party services
4. Click on the Sell button
5. Choose the cryptocurrency you want to sell and choose the exchange currency UAH
6. Enter the amount of cryptocurrency you want to sell and click the Sell button
7. Select the GEO Pay payment service and click the Sell button
8. Pass the SMS or Authentificator verification by entering the code and clicking the Next button
9. Confirm the transition to a third-party payment service in the window and click the Go to GEO Pay button
10. In the GEO Pay payment window, enter the card details and click the Sell button (see the diagram below)