Step into

Meaning

To start doing something, or become involved in a situation.
To enter a place, situation, or role often implying a transition or beginning of involvement.

I’ve completed the report for you.

Great.
Step into my office.

Sure.
But I’ve only got 10 minutes.

Why don’t you leave it on my desk and I'll look at it later.

You seem very annoyed.

It’s just that she’s always stepping in.

Are you talking about your roommate?

Yes.
She’s great but sometimes I just need my space.

"Step into" can be both transitive and intransitive and it’s an inseparable phrasal verb.

Intransitive: When it is used without a direct object. It doesn’t require an object to complete the meaning.
Example: As soon as she stepped into the room, everyone stopped talking.
Example: We can discuss it over coffee, care to step into my office?
Transitive: When it is used with a direct object, it takes one.
Example: He stepped into his new job after graduation.
Example: Getting married was fun but I found myself stepping into a whole new world.
Inseparable: You cannot separate the verb step from the particle into without affecting its meaning.
Example: He hesitated before he stepped into the conversation.

Related words: access, enter, gain entrance, set foot in