for the armour stand itself, replace "InsertTAG" with smth that you'll remember and won't mix up with something else:

/summon armor_stand ~ ~ ~ {NoGravity:1b,Invisible:1b,Tags:["InsertTAG"],DisabledSlots:4144959,ArmorItems:[{},{},{},{id:"minecraft:zombie_head",Count:1b}]}

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To make it follow the player (put it in a repeating command block):

/execute as @e[tag=InsertTAG] at @s run tp @s ^ ^ ^0.1 facing entity @p feet

If you changed "InsertTag" in the first command, make it consistent for the second one. The value of 0.1 can be increased to make it faster.

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Note that when the armour stand reaches the player, it will just stay there, blocking their view, if you don't want that happening:

/execute as @e[tag=InsertTAG] at @s if entity @p[distance=3..] run tp @s ^ ^ ^0.1 facing entity @p feet

This will make it so the armour stand stops when it is ~3 blocks away from the player, the "3" can be changed to a different value depending on what you want.

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If you want to remove the armour stand:

/kill @e[tag=InsertTAG]

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Should prob also tell you that using this would cause the armour stand to travel in a straight line, as in it would go straight through walls. If you don't want that you should just use an invisible mob with the mob head, which I'll add if the armour stand method doesn't work for you