App installation

I am a starter. Home assistant app installed on iPad. Do app installs HA instance?. If so I am unable to connect

It is actually called Home Assistant Companion App and it requires a Home Assistant server.
Many start out with a Raspberry Pi4 with 4Gb and a 32GB SDcard for the server.
An old laptop can often also work, but HA needs UEFI boot.

It is not possible everything on mobile without pi,Linux or others.

No it isn’t.

Thanks a lot for clearing me.