You can suggest things to your local Party members, that get brought up in local meetings. Then eventually these might make their way into the ear of some higher-level officials with the power to make it happen.

Or, you call a hotline and complain about something. A bureaucrat then gets working on it. The national hotline is 12345 to complain about things that aren't working.

Or you post on social media and eventually, if the post becomes popular, Party officials see it and take action.