From Hard Drop - Tetris Wiki
The game interface appears on screen while the Player is playing a Tetris game. It is superimposed on their view of the game.
 Singleplayer interface
1. Hold Queue: The storage place where players can Hold any falling Tetrimino for use later. When called for, the held Tetrimino swaps places with the currently falling Tetrimino, and begins falling again at the generation point.
2. Next Queue: Displays the Next Tetrimino(s) to be placed (generated) just above the Matrix. In guideline Tetris games, 3 Tetriminos are shown, while in older games, only one is shown.
3. Score: Displays how many points the player has.
4. Lines: Displays how many lines are cleared in Marathon or remaining in Sprint.
5. Level: The current level the player is on.
6. Time: In non-Ultra modes, it shows how long they have played.
7. Playfield: The grid into which Tetriminos fall.
8. Active Tetromino: The falling Tetrimino.
9. Ghost Piece: A graphical representation of where the Tetrimino in play will come to rest if it is dropped from its current position. Appears as an outline or translucent image. Begins North Facing at generation.