Pressing F7 while in a match opens the abuse report tool. You can select the "Abusive Player" or "Abusive Game Server" checkbox and choose a reason, such as cheating, chat abuse, or inappropriate decals.
If you need to report someone for , scams , or abusive behavior , there are several ways to do so directly through the Team Fortress 2 and Steam interfaces: Team Fortress 2
You can also report players by clicking the "Report Player" button on the main menu (ESC) or right-clicking their name on the scoreboard during a match. Other Types of Reports Guide :: Filing an Abuse Report - Team Fortress 2 Pressing F7 while in a match opens the abuse report tool