Does my connection switch automatically when using an Access Point?

Hi,

I am looking to buy an Access Point for my home wireless network because my AC router doesn't quite reach where I need it to reach.

If I connect an ethernet wired Access Point to the router will my devices automatically know to switch to the Access Point when it has a stronger signal than the router?

My understanding is that the SSID and passwords etc would be the same for the Access Point and the router - is that confirmed to be true?

Thanks!
Juggernaut