A Dungeon Master screen is something used by almost every Dungeons & Dragons group and most are purchased by the DM for use in their games. Wizards of the Coast offers several official DM screens that can be purchased, featuring beautiful artwork and helpful rules notes for the DM to keep track of. There are even D&D products that come with DM screens, such as the D&D Rules Expansion Gift Set. A DM might want to consider creating their own custom DM screen, either due to financial issues, or because they want a specific set of notes printed on the back for use in their game.
The DM screen is a long piece of cardboard that is broken into four segments, allowing it to stand up on its own. The DM keeps it in front of themself on the table, creating a barrier between themselves and the player. The DM screen exists for several reasons, the most important of which is to hide dice rolls. The players generally roll their dice out in the open, while the DM rolls their dice in secret, in order to keep the players guessing. This obstruction also gives the DM the chance to cheat and lie about their dice rolls, in order to save a player character from certain doom or to prevent an action that could derail the campaign. The other use for the DM screen is to hide the DM's D&D adventure notes and maps so that players can't have a peek at them and see what's coming up next in the game.
Related: D&D: Fictional Languages You Can Use In A Campaign
It's easy for a D&D player to take up the hobby, as all they need is a set of dice, paper, and a pencil. All the group needs is a single copy of the Player's Handbook to contain all of the rules they need for creating characters and running games. The DM of the group doesn't have it quite as easy,
Read more on screenrant.com