how to turn single element in a list into element haskell code example

Example 1: first element in list haskell

list = [1, 2, 3]

head :: [a] -> a
head (x:_) = x

head list -- 1

Example 2: remove first element list haskell

a = [1, 2, 3, 4]
b = tail a
  
-- b == [2, 3, 4]