I am implementing an app through Xamarin.
Is it possible to programmatically connect to an SSID which is already remembered by the phone in iOS?
No, it is not possible to connect to a known network, without providing the necessary credentials, due to various security reasons.
In order to connect to a network, you need to create a NEHotspotConfiguration
The class requires either only SSID (for open networks), or SSID with some credentials for authentication.
After the configuration is created, you can connect via NEHotspotConfigurationManager like so:
await NEHotspotConfigurationManager.SharedManager.ApplyConfigurationAsync(config);
NB: Keep in mind that to connect to a network, you need to enable the Hotspot
capability in your App Capabilities Working with capabilities.