The Diablo 4 HUD is consistent with previous Diablo games. Skill bar a long the bottom along with resources and other indicators such as a dodge time and buff indicators.
Can you change or move the HUD?
The HUD can be changed but only slightly as of launch. It can me moved from the center bottom of the screen to left side via a setting in the options.
Go to the options, select Gameplay and look for a setting called HUD Configuration and wither select centered or left corner.
HUD Left
HUD Right
Can you remove the HUD?
Not at the time of launch. You cannot remove the HUD for screenshot purposes. Hopefully this will become an option in the future.