In to VS into

Correct: “The robbers will break in to the bank at 6pm.” (bandit) The phrasal verb is ‘break in,’ meaning to enter without permission. “In” is part of the verb and the preposition is “to”.
Incorrect: “The robbers will break into the bank at 6pm.” The phrasal verb has been corrupted.

Correct: “I’ll look into this matter before the end of the day.” The phrasal verb ‘to look into’ means to investigate.
Incorrect: “I’ll look in to this matter before the end of the day.” The back-to-back prepositions in this phrase signals the error.

Correct: “Turn your paper in to your teacher.” The phrasal verb ‘to turn in’ means to submit. In is part of the verb and to is the preposition.
Even better: “Turn in your paper to your teacher.” The phrasal verb is kept together.
Incorrect: “Turn your paper into your teacher.” Shazam! Your paper is now your teacher. :O ‘To turn into’ is another phrasal verb meaning to transform. Surely, that’s not what you meant.

Correct: “I am really into alternative music.” The phrasal verb ‘to be into’ means to be passionate about.
Incorrrect: “I am really in to alternative music.” The double preposition is the clue that there is an error.

Check out the distinction between the following two statements:
-running in the yard
and
-running into the yard.
They mean different things.

More:

“Turn in” to to mean ‘drive into’, ‘walk into, etc.

“Turn into” to mean ‘transform into’.

Examples:

“He turned the car in to the cul-de-sac. ”

“He turned the car into gold.”

Using our lingo as examples:

“When specifying a name, take into account special <a href=”#Rules”>rules</a>.”

“Place this file in the newly created folder.”

(While it isn’t incorrect to say “Place this file into the newly created folder”, using American Standard English you would actually say “in the newly created folder”. Using “into” here is actually British English usage. Since this distinction is not really made by most people, you guys can use whichever in this particular case. (whew))