what are the documents needed to travel?

hi. I'm indian citizen. I'm planning to visit Vietnam next year.I never traveled outside country.so here is my question.WHAT ARE THE DOCUMENTS NEEDED TO TRAVEL TO VIETNAM OTHER THAN PASSPORT?AND IF I'M GOING BY FLIGHT WITH STOPS IN BETWEEN,WILL I NEED ANY VISA OR DOCUMENTS OF THE COUNTRY WHICH THE FLIGHT STOPS?please help.