Using the bare domain and www

When you connect yourcompany.com Praxivara sets up www.yourcompany.com too. The panel shows a record for each: the bare domain and www. Add both and visitors reach your app either way.

Only want a subdomain?

Connect app.yourcompany.com instead. That is one record and leaves the rest of your domain untouched, which is the right choice when your main website lives elsewhere.

Already using the bare domain for another site?

Use a subdomain for the app. A domain can only point at one place.