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:
Into is one word.
no it is not an one word it is of two word
I think the word "ongoing" is only one word, but it has two syllables that are two separate words.
It is one word.
one word
Toenail is one word.
"Bookwork" is one word, not two.
no it is not an one word it is of two word
Hipbone is one word.
I think the word "ongoing" is only one word, but it has two syllables that are two separate words.
One word, two syllables
It is one word.
one word
"Hardworking" is one word.
Toenail is one word.
one word
"Doorway" is one word.
"Foolproof" is one word.