How to report harassment taking place within Battle.net chat (mobile or desktop)
How to report a player for cheating in Diablo III
Reporting your own behavior won't prevent action.
How to report players in Diablo III.
How to report abusive content in a Blizzard game, platform, or forum.
How to report a player who is threatening with harming another person or a place
How to report another player that is using an offensive or inappropriate BattleTag