I think it's:
The exclamation point!
My reasoning:
I am something that everyone needs.
You use me many times in different ways.
Everyone uses it, and for a variety of reasons. Linguistics, coding, etc.
Sometimes you only use part of me,
The dot at the bottom is a period.
Others you only use most of me.
A vertical line by itself can be an L, pipe (|), or a 1.
You always turn and bend me to your will.
You use to me to scare, to confuse, even to question.
Turn it upside down and it makes a lower case i, which appears in "will". Turn it on its side and it becomes Morse code for A (._
) or N (_.
). You can bend it into the shape of a question mark (?) or a lower case j. There are lots of reasons and ways to use an exclamation point, so you can shape it to fit your meaning ("bend it to your will"), both literally and figuratively. An exclamation can be used to scare, confuse, and (rhetorically) question.
You can even use to confront someone like when you say "Bill, [rest of confrontation]"
We speak with passion during confrontations, calling for this punctuation mark.
You absolutely use me every day.
We all get excited or emphatic when speaking sometimes, and of course we use it to make spoiler tags for answers posted here on Puzzling.
And finally...
There's this comment, though I thought of this as the answer before I saw it.
Turning my original answer on its head, a stronger possibility is:
The letter i
I am something that everyone needs.
You use me many times in different ways.
"Eye" is pronounced the same as "i". "Everyone" contains "eye" and "different ways" contains both "eye" and "i". Everyone needs both the letter i and their eyes, and uses them frequently for various purposes.
Sometimes you only use part of me,
Others you only use most of me.
What I said about the shape of the exclamation point applies here as well, but there's more. How much of your eyes you show varies with circumstance (squinting, winking, etc.; the size of your pupil depends on the amount of light) and emotion (surprise, sleepiness, etc.)
You always turn and bend me to your will.
You use to me to scare, to confuse, even to question.
All the reasoning about the shape of the exclamation point applies here as well; you can get lots of utility and different meanings out of this shape ("i" or "!"). But you can also use your eyes to express the emotions mentioned. You do this by moving or reshaping them ("turn and bend"), and this can express your desires or feelings ("will").
You can even use to confront someone like when you say "Bill, [rest of confrontation]"
"Bill" contains "i", and the rest of the confrontation is likely to involve some statement like "I know..." as well as angry looks.
You absolutely use me every day.
You use both your eyes and "i" every day, and "every" contains "eye".
And regarding the hints given in comments:
This statement holds true for "i".