No, you cannot work in Vietnam with a Vietnam visa 3 months. You will need to apply for a work visa if you plan to work in Vietnam.
No, you do not need a return ticket when applying for a Vietnam visa 3 months.
Yes, it is possible to extend your Vietnam visa 3 months. However, you must do so before your visa expires and pay the extension fee.
It typically takes around 5 to 7 working days to process a Vietnam visa 3 months application when applying at the Embassy or Consulate.
You will need to submit your passport, a completed visa application form, two passport-sized photos, and the visa application fee.