I often have to hesitate when I want to use “into,” struggling with which is correct – “into” or “in to.”
The main deciding factor is whether there is motion, or action going towards something. Going into a place takes the compound word (into).
Even moving towards something intangible counts.
For example: I moved into a state of depression.
More examples:
I climbed into the cave.
I entered the house and went into the kitchen.
If you mean that you entered a place in order to do something, use the two separate words.
Example:
I am going in to get a coat.
The cave was dark but I went in to explore it anyway.
So, using both:
I climbed into the cave. I went in to explore.
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