I am from south India and recently wanted to learn Bansuri flute so I ordered one online.But later just like you I found out that there are two types of Bamboo flutes :
There are two traditions of classical music in India :
Hindustani music (North-Indian tradition)
Carnatic music (South-Indian tradition)
Bansuri is used in Hindustani classical music (North-Indian) which consist of 6 or 7 holes, where as, the Carnatic classical music (South-Indian) uses the Venu which consist of 8 holes but most of the time only 7 are used.
In the below picture, left one is a Carnatic flute Venu while right one is a Bansuri.Observe the holes :
The main difference in number of holes is because of the fingering is different and also the Venu is said to be able to produce more types of notes than Bansuri.
Bansuri is easier to learn and play for beginners.You can choose either of them.It is better to have a teacher to play Venu, because there are some techniques involved in playing music.Both can play really good music so you can choose either, but beginner should prefer the Bansuri (will have 7 holes + 1 blowing hole).
You should prefer buying a medium sized c or g scale flute, should be of good quality.
I am a beginner like you.Punam flute in amazon.in is a good quality one (just a recommendation not a spam).