Welcome to italki!
Italki is a marketplace that connects paid teachers and students. Teachers list their prices and hours. Students choose a teacher, then choose a time, then take a lesson at that time. After the lesson, the teacher is paid.
Italki also has a language exchange. People who speak language A and who want to practice language B pair up with people who speak language B and who want to practice language A. Sometimes, it is difficult to find a person who wants to learn your language, who is available at convenient times, who actually shows up at the agreed times, who shares the time 50%/50% between the two langauges, and who is interested in topics that you are interested in.
Italki also has forums. There is a question forum for grammar and vocabulary questions. There is a notebook forum for posting texts and getting corrections from native speakers.