Go to the developer console by hitting ~ (the key above the Tab key) and type the following codes for the desired effect.

Code	Effect
bind x firstperson	Bind a key (x) to the command.
bind x thirdperson	Bind a key (x) to the command.
cl_drawhud 0	Remove the information on screen.
firstperson	Go back to first person.
thirdperson	See the game from a third person perspective.