Do all function have inverses ? Why or why not

Do all function have inverses ? Why or why not ?

PLease explain clearly

yes but in some inverses ur gonna have to mension that X doesnt equal 0 (if X was on bottom)
reason:
because every function (y) can be raised to the power -1 like the inverse of y is y^-1
or u can replace every y with x and every x with y

for example
find the inverse of
Y=X^2 + 1
X=Y^2 + 1
X - 1 =Y^2
Y= the squere root of (X-1)