In Safari tap the 3 dots icon at bottom right, in any other browser tap the share icon (usually at the top right) and skip to step 3
In Safari, after having tapped the 3 dots icon, tap the "share" option
In the share menu, tap the "View More" Option
Scroll down and tap the "Add to Home Screen" Option
Change the title if you so please, make sure "Open as Web App" is turned on, then tap "Add"
Place web app icon wherever you please on your home screen
Open web app and set your User ID, it will save to the web app. You only need to do this step once!