Hey Myrto
Anytime :-)
This will depend on the developer and the specific game, but quite often it will probably be you asking a programmer for specific calls to be put into the game code, not the other way around. Generally speaking, it's better to have created the events in Wwise beforehand, perhaps with some placeholder audio, before they are put into game code - so the programmer can make sure that the calls are working correctly when they write them in.
You might also consider learning the basics of how to script in the relevant game engine, so you can create the calls you need yourself. It's easier than it sounds.
If you are working with a well-organized team, you may receive a relatively complete list of sounds needed for the game when you start work, but it varies. And even if you do, you may still have to figure out which specific calls you will need and how to name your events. And invariably, you will discover that you want some additional calls or game parameters that no-one else thought to include.
I often use spreadsheets/Excel when communicating this stuff with programmers, so it's definitely a good option - but again, in my experience the sound designer is the one writing them.
Kind Regards
Tobias