Translated pages same page ID?

Yes, looks like you came to right place! Depending on your theme, you may be required to do some additional configuration:

https://qtranslatexteam.wordpress.com/integration/

but you will not know before you try:

https://qtranslatexteam.wordpress.com/startup-guide/

So the page ID and URL are same for a page123 whether I view this in English or in German?

Page ID is the same, URL may be different depending on URL Modification Mode.
Most people choose Pre-Path for URL modification mode, which make urls look like example.com/en, example.com/xx, etc. Set a test-copy of your site and try it, then you will have more sensible questions ??