Put it at the very start of a scene where someone walks in, joins a call, or interrupts a conversation, then follow it with the DJ Airhorn for a bigger entrance or the Law and Order Dun Dun when that entrance leads into a dramatic reveal.
Über diesen Sound
This is a spoken line lasting just over a second, delivered in a flat cartoon voice as someone announces their arrival with the words 'I come in'. It feels awkward and cheeky, like a deliberately overconfident entrance that lands as a joke rather than a greeting. The line comes from Family Guy.