Player's BackPack

How to add tools to backpack but it should not be displayed at the down part of the screen like tool 1 and 2

You can try doing something with the coregui, theres this plugin called custom toolbars i think and maybe you can make them invisible doing that.

what i understand is you want to hide the backpack gui, you can do that with this

game.StarterGui:SetCoreGuiEnabled(Enum.CoreGuiType.Backpack,false)

(in a localscript)

This would make the backpack completely unusable, being unable to equip any tools.

i see, what you will have to do then is script an inventory system yourself

you cangive a tool to a player by parenting it to their character, make that happen when they press 1 or click on the backpack slot