> For the complete documentation index, see [llms.txt](https://dev.payon.com.kh/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://dev.payon.com.kh/how-to-implement/how-to-implement-qr-payment/web-base-implementation/step-3-notify-processing-payment.md).

# Step 3: Notify Processing Payment

This step will be call to notify PAYON's Aggregator when mobile app already authenticate with user

![Figure 03: PG Processing Screen](https://3248127681-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FfVqIgxK8Sk7FYmeRNmqq%2Fuploads%2Fkx4RUeyVgvj9zpglKBRf%2FScreenshot%20from%202021-12-02%2010-10-02.png?alt=media\&token=63b8233a-ddba-46a9-8184-94e48f5ab531)

After complete [STEP 1 ](/how-to-implement/how-to-implement-qr-payment/web-base-implementation/step-1-prepare-to-read-khqr.md)& [STEP 2](/how-to-implement/how-to-implement-qr-payment/web-base-implementation/step-2-notify-qr-scan-screen.md),  3rd party mobile app will display payment information for user to authenticate the  payment through  any authentication method such as PassCode, Fingerprint and Face recognition etc. This step request to call to notify to PAYON's aggregator to change to screen "QR Processing Screen".  Please follow [Notify Processing Payment API](/payon-api-rerferences/qr-payment/notify-processing-payment.md) for more detail api specification.