be in
phr. v..phr. v.. to be at home or in your office when someone visits or calls.
phr. v.. to be present at a specific location, typically one's residence or place of work; functions as an intransitive phrasal verb in this sense.
I'll be in all morning if you want to call.
The manager won't be in until Tuesday because she is attending a conference.
Despite the lights being on, nobody seemed to be in when the courier attempted to deliver the package.
often used in the negative to explain someone's absence.
contrast with 'be out'; note that 'be in' can also mean 'to be fashionable' or 'to have submitted work', but the 'present' sense is most common for A2 learners.
Is your boss in to his office?Is your boss in?when 'in' means 'present', it does not require a following prepositional phrase like 'to his office'.