How to use mobile ID app?

Could you please elaborate on the steps involved in utilizing a mobile ID app? I'm particularly interested in understanding the process from start to finish, including any necessary setup or verification procedures. Additionally, I'd like to know if there are any specific security measures I should be aware of when using such an app to protect my personal information and transactions. Lastly, are there any common issues or challenges that users may encounter when first starting out with a mobile ID app, and how can these be resolved?