How do i tell my girlfriend that i love her so much?

Be faithful, kind and thoughtful.

"I love you so much"

Don't use any words....let her see it in your eyes...

Speak her love language. Either with words,
gifts,
physical touch (not always sexual)
quality time, or
acts of service.

If you dont know her love language, have her take the quiz.

If you want to show her, plan something nice for her based on what she enjoys...what sort of hobbies or interests does she have?

Otherwise just telling her and giving her a hug suffices

Actions speak so much more loudly than words.

Why do you need to ask. If you love her so much it should not be hard.

Behave accordingly

Using your vocal cords.

let her sit on ur face

Get naked in front of her.
Get onto your knees and look her in the eye as you nossel into her crotch.
Use your hands to hold onto her butt cheeks.
Tell her that you cannot live without her as your master and you will do anything and everything to make her happy in life..
Then bow and lick her toes/feet/shoes as a sign of your submission to her authority over you..

That is if you really mean that you love her...