Do we get H4 approval notice if we get first H4 visa directly in india using H1B approval notice and come to USA

USA H4 Visa
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  1. Do we get H4 approval notice if we get first H4 visa directly in india using H1B approval notice and come to USA…
  2. Planning to go for H4 extension dropbox, what are the document checklists…?
  3. Also which one preferrable dropbox or inPerson Interview…?
    thanks in advance