Opening with 2 pawns on one move

Nope, not legal. The only time you can move two pieces at once is when you castle.
I've never heard of that. I thought there were no situations where you could move two pieces at once. I was taught that even in castling you can only move one piece at a time. The king two squares over, then the rook over the king. Never both at once. But I guess it would be like capturing a piece. Some people move both pieces at the same time, others just one at a time.

So i was with some friends the other day and i was playing with one of them on a chessboard, with him being black and me white. After my first move e4, he moved his 2 e7 and d7 pawns on e6 and d6, and even though i asked the eligibility of his move, he insisted it was a legal move. I was startled because i haven't heard about it nor can it be used in online chess. Even a friend of ours said he knew of it and that it was legal. So if any of you could confirm whether this move is eligible or not would be quite helpful
Think about it... you moved 1 pawn 2 spaces, right? So it's only fair that your opponent should be able to move 2 pawns 1 square each. Otherwise, if he only moves 1 pawn 1 square, isn't he at a disadvantage?

Nope, not legal. The only time you can move two pieces at once is when you castle.
I've never heard of that. I thought there were no situations where you could move two pieces at once. I was taught that even in castling you can only move one piece at a time. The king two squares over, then the rook over the king. Never both at once. But I guess it would be like capturing a piece. Some people move both pieces at the same time, others just one at a time.
It's great that you bring up the metaphysics of castling, as it is an important subject that is discussed far too rarely. You may be interested in a piece I once wrote on the subject:
https://www.chess.com/forum/view/general/castling-and-the-4th-dimension

Nope, not legal. The only time you can move two pieces at once is when you castle.
I've never heard of that. I thought there were no situations where you could move two pieces at once. I was taught that even in castling you can only move one piece at a time. The king two squares over, then the rook over the king. Never both at once. But I guess it would be like capturing a piece. Some people move both pieces at the same time, others just one at a time.
By the usual rules you can only use 1 hand when moving so yea, you have to move first the king and then the rook (if you touch first the rook your opponent might call in "touch rule" and you end you moving only your rook). You physically move then one at a time but its counted that you move 2 pieces on the same turn.

In all seriousness, I've witnessed so many weird examples of magic chess when playing casual games, that I'd suggest you to join a club to play OTB if you don't want to spend half of the time on endless discussions.

Ignore the trolls.
I have heard of this. If you go to a chess cafe most old guys will do that. They believe that if you don't play 1 pawn 2 squares in your first move, you can play 2 pawns one square. Of course, it's an urban myth and nothing more.
You can't move 2 pieces or pawns at any point of the game except only once, in castling. Castling is also the one and only case in which the king can move 2 squares and the rook can jump over a piece but although technically it's a 2 pieces move, it is considered one move.
I agree. Ignore DeirdreSkye.

In Indonesia I've encountered that 2-pawns move by 1-square at opening a lot. They are surprised, when I tell that it's an illegal move.
Would be nice to know where that rule came from.
This is a persistent misconception among hobby players.
The Laws of Chess are clear:
3.7.1
The pawn may move forward to the square immediately in front of it on the same file, provided that this square is unoccupied, or
3.7.2
on its first move the pawn may move as in 3.7.1 or alternatively it may advance two squares along the same file, provided that both squares are unoccupied, or
3.7.3
the pawn may move to a square occupied by an opponent’s piece diagonally in front of it on an adjacent file, capturing that piece.
https://handbook.fide.com/chapter/E012018
So i was with some friends the other day and i was playing with one of them on a chessboard, with him being black and me white. After my first move e4, he moved his 2 e7 and d7 pawns on e6 and d6, and even though i asked the eligibility of his move, he insisted it was a legal move. I was startled because i haven't heard about it nor can it be used in online chess. Even a friend of ours said he knew of it and that it was legal. So if any of you could confirm whether this move is eligible or not would be quite helpful