I want to know to create a secure certificate for my UWP Project in Visual Studio 2017

I have an UWP project, the certificate that I created was the option of Test Certificate that expire in 1 year. I package the app and the app security certificate say "Approved". When I send the .appxbundle to my friend because he wanted to test my app, the installer said "The certificate is not trusted Error (0x800B0109).

In order to side load an app, the machine needs to have trust for the certificate from the app developer (assuming side-loading is enabled in settings).

When you package your app within VS, there's usually a PowerShell script next to the deployment package. If they use that script, it should prompt to install the certificate as well.

Otherwise, they can manually import the certificate to their Trusted People store in order to install the appx.