Marta studia; inoltre, lavora.

Italian often leaves out the subject when it is already clear. After Marta studia, the reader already knows the subject is Marta, so lavora is naturally understood as Marta lavora.

You could say Marta studia; inoltre, lei lavora, but lei would usually add emphasis or contrast. In a neutral sentence, leaving it out is more natural.

Both are third-person singular present indicative forms.

• studia = he/she studies
• lavora = he/she works

Because the subject is Marta, they mean she studies and she works.

In Italian, the present tense is commonly used for things that are generally true, habitual, or current.

So Marta studia and lavora mean that studying and working are part of her current situation or routine. This works much like English Marta studies / Marta works.

Inoltre is a connector meaning moreover, furthermore, or in addition. It adds another piece of information.

Here it links the two ideas:

• Marta studia
• inoltre, lavora

So it is not changing the basic meaning of lavora; it is just showing that this is an additional fact.

Yes, but it sounds a bit more formal or written than some alternatives.

In everyday speech, Italians might more often say:

• Marta studia e lavora.
• Marta studia, e in più lavora.
• Marta studia; inoltre, lavora. is correct, but slightly more polished or formal.

The punctuation shows that inoltre is being used as a linking adverb between two complete clauses.

• Marta studia = a complete clause
• lavora = another complete clause, with the subject understood

The semicolon helps separate two closely related statements. The commas set off inoltre as a parenthetical connector.

You may also see other punctuation, such as:

• Marta studia. Inoltre, lavora.
• Marta studia e, inoltre, lavora.

All are possible, though the original sentence has a more formal written style.

Yes. That is probably the most natural everyday version.

• Marta studia e lavora = simple and common
• Marta studia; inoltre, lavora = more formal and more explicitly additive

So the original is not wrong at all; it just has a slightly different tone.

Sometimes, but not in exactly the same way.

Anche usually means also/too and often attaches more directly to the word or phrase it modifies:

• Marta studia e lavora anche.
• Anche Marta lavora. = Marta also works / Marta too works

Inoltre works more like a sentence connector: furthermore / in addition. It adds a whole new statement.

So inoltre and anche can overlap in idea, but they are not always interchangeable.

No object is required here. Studiare can be used intransitively in the general sense of to study.

So:

• Marta studia = Marta studies / is studying
• Marta studia medicina = Marta studies medicine

Both are correct. The version without an object just leaves the field or subject unspecified.

Yes. Lavorare can also stand alone.

• Marta lavora = Marta works
• Marta lavora in banca = Marta works in a bank
• Marta lavora come insegnante = Marta works as a teacher

So, just like in English, the sentence can be complete even without extra details.

It would not be grammatically wrong, but it would sound a bit repetitive unless you want emphasis.

Italian usually avoids repeating the subject when it is obvious. The shorter version is smoother:

• Marta studia; inoltre, lavora.

If you repeat Marta, it can sound more deliberate or emphatic.

It can move, although some positions sound more natural than others.

Possible versions include:

• Marta studia; inoltre, lavora.
• Marta studia; lavora inoltre.
• Inoltre, Marta studia e lavora.
  (This changes the structure a bit.)

The original placement is very natural in formal writing because inoltre clearly introduces the second clause.