Places that only exist for apps: store nominations, in-app events, public betas and app communities.
Check the developer post rules and flair. Be clear about price, ads and permissions; that is what people ask about first.
Post: Show what you made and ask for feedback. Follow the community rules on self-promotion.
This one lives inside the store or an app community, so it only applies to apps. In the workspace, Groivo gives r/androidapps its own App Store campaign link (ct=) and Google Play referrer, so downloads from it show up in App Store Connect and Play Console.