"You are learning from him."
Translation:Du lernst von ihm.
vom is a contraction of von dem "from the", for masculine and neuter nouns.
For example, Du lernst vom Lehrer "You learn from the (male) teacher".
But Du lernst von der Lehrerin "You learn from the (female) teacher".
The preposition von requires that whatever coming immediately after it is in dative case. The dative male pronoun is ihm (and ihn is accusative case).
No. You can't use one for the other in German.
In English, they are often both "him" because English merged the old dative and accusative cases of old English into one objective case.
But German still keeps them separate.
I put 'ihr learne aus er' which is obviously so wrong but then I thought I'd put it into Google translate and is came back as 'you learn from him'. So at least Google understands me!