iOS - Safari currently doesn't support a Web app install banner, like in Android - Chrome.
There is no way to programmatically trigger install banner in Android as well, except for the case when you catch the beforeInstallPrompt and use that to show the banner.
In the linked answer, you can check on the alternate option on how to show in app banner to guide user to add to home screen. Here is some code example for the same, which is iOS specific (look under #PROTIP 3).
Answer from Anand on Stack OverflowiOS - Safari currently doesn't support a Web app install banner, like in Android - Chrome.
There is no way to programmatically trigger install banner in Android as well, except for the case when you catch the beforeInstallPrompt and use that to show the banner.
In the linked answer, you can check on the alternate option on how to show in app banner to guide user to add to home screen. Here is some code example for the same, which is iOS specific (look under #PROTIP 3).
For now, Apple doesn't give the possibility to make this "Add to home screen" experience easy.
You can provide a tooltip explanation to your users though, for IOs users:
Details explained here: https://web.archive.org/web/20200809175125/https://www.netguru.com/codestories/few-tips-that-will-make-your-pwa-on-ios-feel-like-native
in the section: PROTIP 3: Create an “Add to home screen” popup yourself!
Videos
I ported the mildly popular react-ios-pwa-prompt into svelte, and creatvely called it svelte-ios-pwa-prompt.
Basically you import this component into your +page.svelte or +layout.svelte and it will magically show a prompt to tell users the steps to add you app to their home screen. Customizable on how many visits before you want it to show and how many times you want it to show up.
» npm install react-ios-pwa-prompt