Here’s a quick and dirty summary of what’s required to distribute your IOS and Android apps from website. For IOS, you need an enterprise developer account and the appropriate enterprise distribution ad hoc provisioning profile. For android, you need to sign your app per instructions pinned in the android section. Once you have created your .APK and your .ipa files, all you need is a website with an SSL certificate, that can be self signed, and upload your .APK and .ipa files to the root directory along with the three attached files. Modify the attached index.html and manifest.plist files to match your domain and App name accordingly. Access the website from your device can you should be able to download and install your app.