What is the best defence with black with white playing 1 E4
There is no "best". There are 4 moves that are stronger than the other 16, and which of the 4 is best depends on which you best understand. What is best for one person may not be best for someone else.
Those 4 moves are:
1...e5 - Leads to a number of various Double King-Pawn openings
1...c5 - The Sicilian Defense, which has numerous variations, along with numerous "Anti-Sicilians", which are still Sicilians, just not the "Open" Sicilian.
1...e6 - Known as the French Defense. There are really 5 lines you need to know. Sure there are some real offbeat sidelines, but the "big 5" are 3.Nc3 (which can lead to the Winawer or Classical, depending on Black's choice), the Tarrasch, the Advance, the Exchange, and the King's Indian Attack.
1...c6 - Known as the Caro-Kann Defense, which has 5 main responses and a few offbeat sidelines. The "big 4" in the Caro are the Classical (3.Nc3), Exchange (3.exd5 and 4.Bd3), Panov-Botvinnik Attack (3.exd5 and 4.c4), the Advance, and the Fantasy Variation (3.f3).
For me, that personal preference is 1...e6. But that doesn't make 1...e6 the best move for everyone. There are other defenses that are not "refuted", but they are weaker. Look at these 4, and simply go with the one that you best understand. Go through maybe 10 games of each opening (GM Level games, not the garbage played here), and try to make sense of what both sides are doing with each move. The one that you are best able to understand is the one you should study in depth.
What is the best defence with black with white playing 1 E4