Is into one word or two?

Answer 1

It is both one word and two words, depending on the context.

"Into" is a preposition which means "to the inside or interior of something".
Example sentences for "into" are:

• Put these into the box please
• He crawled into his bed

"In to" is used as part of a verb phrase.
Example sentences of "in to" are:

• The police officer ran back in to save the woman.
• He gave in to the peer pressure.

Answer 2

Into is one word.