How can I flip and mirror the picture on my webcam

You can mirror or flip in OBS Studio.
 
OBS Studio
https://obsproject.com/
 
If you are using Windows OS, please reach out to our support team at TechnicalSupport@avermedia.com , we will provide you the driver which can allow you to mirror or flip in other 3rd party software, or install below directly:
https://drive.google.com/file/d/1KUTOl5U34ljv2Pgd80rUkxvN3Coh8rCB/view?usp=sharing

Please follow the below video once you received the driver: 


Feb 2021
Revised Mar 2021