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Thank you for bringing up your question! What I believe you are talking about is the scoreboard. You can resize this scoreboard by changing the GUI scale in your Minecraft video settings. If you want to remove it, type /me in chat and click "settings". This will open a GUI where you can remove the scoreboard.
I hope this helps! If you have any other questions, please reply below or create an in-game support ticket with /t create. Have a nice day!