Allow chrome to install app from unknown source
As this application is not downloaded from the Play store, it is important to allow installation from external sources
For Samsung devices:
Settings>>Biometrics and security>>Install unknown apps>> Toggle Allow from this source.
For non-Samsung devices:
Settings>>Security & privacy >>More settings>> Install apps from external sources>> select chrome and toggle Allow app installs.
For iOS users
The applications are not available in the app store; instead, you can Add the website page to Home Screen.
Open Safari, browse to https://www.amretina.com, press the share button, and then choose to Add to Home Screen.