Context: I invited a person to participate in a chat. チャットに参加してください was my original sentence. Is my sentence and word choice correct? I was considering the word 関与.
関与 is a stiff word that refers to a serious and responsible involvement/engagement with a project, mission, contract, criminal case, and so on. It's not a light word used with casual parties, picnics and chats.
BTW, It's time for you to learn to use advanced learning materials before asking many questions here. Try ALC, Weblio and BCCWJ, and you should be able to understand 関与 is not the right word for a casual chat. If these still didn't help, be sure to include your previous research in your question.