Translate to or translate into?

Into English is the correct one

Either can be used, but "into" is better for formal situations, and it's used more commonly in this context.

"Translate into" is what I would use.This is a phrasal verb and 'into' is the correct fit rather than to.

Often the choice comes down to usage norms and/or style choices.

For example, days of the week . . . The proper grammar rule is "on" for days of the week. But often "on" gets dropped. Thus: See you on Tuesday . . . or . . . See you Tuesday are both correct and natives will often drop out the preposition "on" because it isn't necessary.

Prepositions are function words and there is some overlap as far as more than one being able to have an equivalent function. For example, "I need to give my parents a call. I haven't talked to them __ over a month."

This example has two options:

1. I need to give my parents a call. I haven't talked to them in over a month.

2. I need to give my parents a call. I haven't talked to them for over a month.

In the case of your question: There is a nuanced difference in usage.

"Into" would usually be the preferred choice if translating a full text from one language "into" another is happening.

"To" would usually be the preferred choice if a phrase or short sentence is involved. Thus the English to Italian translation for Good morning! is Buongiorno! Thought of in this way, the English phrase "Good morning" corresponds to the Italian phrase "Buongiorno". It is not thought of as a text transformation in the same way as it is with text translation.