Correct spelling, explanation: in to is a combination of the preposition in and the preposition to. It is used when in is part of a verb phrase and to is a separate preposition indicating direction or purpose. Into is a single preposition that indicates movement or a change of state from one place, condition, or situation to another. In to is used when in and to have separate functions within a verb phrase. The distinction lies in their grammatical usage and the way they convey meaning in a sentence.

Correct spelling, explanation: into is a preposition that indicates movement or a change of state from one place, condition, or situation to another. It is used to show the direction of action, often involving physical movement, transformation, or change of condition. The word into originated from Middle English, combining the words in and to. In Old English, the word in indicated a sense of location, while to indicated direction. Over time, these elements were combined to form into as a distinct preposition. Into is different from in to.

Definition of into:
1. preposition, to the inside of; in toward
She jumped into the pool.
She carefully placed the key into the lock and turned it, opening the door to her apartment.
2. preposition, used to say that someone has become involved in something
Mark wants to get into politics.
She immersed herself into the world of art, spending hours painting and exploring different techniques.

Collocations with into:
Some most commonly used collocations include:
1. Walk into: to enter a place on foot.
She walked into the coffee shop and ordered her favorite latte.
2. Run into: to encounter unexpectedly.
I ran into my old friend at the supermarket.
3. Break into: to forcibly enter a building or place, often illegally.
The burglars tried to break into the jewelry store.
4. Settle into: to become comfortable and familiar with a new environment or situation.
It took a few days for her to settle into her new apartment.