You have to figure out where to get the game hosted. If it can be a simple zip or rar file, you could put it on Dropbox or another such site. Not sure if this addresses your question!

Then you can tell our community about your game in the Your Announcements board. There are different kinds of feedback - design feedback, to improve the game's playability, and market feedback, to determine whether money should be invested on it. For example. Just asking for “feedback” probably doesn't get you as much useful feedback as a specific request would.

@chiffre If you don't have people to share it with currently: I personally run a discord server where I share updates on games I make for others to test out/play. Over 6 months I got 15-20 people in it. I grew it to that number by talking about it and inviting others from other discord servers I'm in(Don't spam other servers talking about your server).

If you got people, but don't know where to host: itch.io is a rly good website to put your games on, I've put all my games worth sharing on there.

Hope that helps!

chiffre said:
Is the latter even an option nowadays?

Yes, it still is an option. It always was. Some places do allow you to store files and share (there are Projects even here, on GameDev.net). Using your website is generally the most straightforward way to share to SPECIFIC people - just put archive up and send link. Using itch.io or other requires additional setup - while good for distributing to others, for testing purposes it requires too much additional work.

It often helps to ping other people directly with test request (I do ask some people I know at least a bit to test - with most of them we work on basis of “You test mine app, I test your app"), or start a thread in good community (i.e. for games - gamedev.net can be good).