In Harry Potter how do they communicate?

Answer 1

The main methods of communication in the wizarding world are:

• Owls - only usually used for sending letters and packages always find the receiver unless intercepted.
• Normal face-to-face communication
• The Floo Network - people can be transported fully or just transport their heads to another place. This communication method is often used for delivering urgent messages or when there is a risk that an important message sent by an owl could be intercepted.
• Patronuses - as well as guarding the user from Dementors, Patronuses can also be used to send messages. This method is usually used to send urgent messages or to send a message to someone whose fireplace is being watched, making it impossible to use the Floo Network. Not many people know how to do this.
• There is also Lord Voldermort's clever idea on his death eaters: loyal servants had a small 'design' of the dark mark branded onto the inner forearm of their left arm. Every time the dark lord touched a mark on one of his death eaters the others could feel it too and was expected to apparate immediately to his side.
• Apparation, a witch or wizard could appear or disappear at will and arrive at a specific destination almost immediatly.
• The DA coins, someone could write a message where the goblin who made the coin would normally be to tell others thing with out appearing to do so.
• Occlumency and Legilimency - someone with the ability to do it could read each others minds.

Answer 2

They talk, like normal human beings.

And for wizards, they use their wands to call people, and they can also speak through fire.

Lord Voldemort (the bad guy) can make a "Death Mark" (to show that he has killed someone) in the sky. The Death Mark is a skull-shaped black cloud figure in the sky. The Death Mark was first introduced and used in the 6th book, "Harry Potter and the Half-Blood Prince."

Answer 3

Just like in the rest of the wizarding world, letters and messages were sent via owls.