user23758: I have asked a few of my friends to join this website and help it improve itself. But I wanted to contact them via this website, of course by chat. But how can I start a chat and invite users?

user9307: You can create chatrooms here, if you have at least 100 rep. However you only need 20 rep to talk in chat. (stop by our main chatroom here to say hi).
If you're interested in knowing how to invite ppl to a chatroom, take a look at this answer. 
If you want to chat privately, I'd recommend using Discord or Skype (or whatever service you prefer) as all the messages are visible to everyone (and also indexed by google) on chat.stackexchange.com.

23758: <p>I have asked a few of my friends to join this website and help it improve itself. But I wanted to contact them via this website, of course by chat. But how can I start a chat and invite users?</p>
 9307: <p>You can create chatrooms <a href="http://chat.stackexchange.com/rooms/new">here</a>, if you have at least <a href="https://anime.stackexchange.com/help/privileges/chat-rooms">100 rep</a>. However you only need <a href="https://anime.stackexchange.com/help/privileges/chat">20 rep</a> to talk in chat. (stop by our main chatroom <a href="http://chat.stackexchange.com/rooms/6697/maid-cafe-">here</a> to say hi).</p>

<p>If you're interested in knowing how to invite ppl to a chatroom, take a look at <a href="https://meta.stackexchange.com/a/99394/174176">this answer</a>. </p>

<p>If you want to chat privately, I'd recommend using Discord or Skype (or whatever service you prefer) as all the messages are visible to everyone (and also indexed by google) on chat.stackexchange.com.</p>
