How many illegal moves are allowed in the recent rules worldwide

Can you please say how much because I lost a  offline game due to 1 illegal move . Pls say so that i can check into the game 

I think two illegal moves are allowed. The second time you make an illegal move you lose.

Yes even I thought the same but my teacher said only one according to new rules so I need a expert to say correctly so that I can say my teacher 

For classical time control:

7.4 a. If during a game it is found that an illegal move, including failing to meet the
requirements of the promotion of a pawn or capturing the opponent’s king, has
been completed, the position immediately before the irregularity shall be
reinstated. If the position immediately before the irregularity cannot be determined
the game shall continue from the last identifiable position prior to the irregularity.
The clocks shall be adjusted according to Article 6.13. The Articles 4.3 and 4.6 apply
to the move replacing the illegal move. The game shall then continue from this reinstated position.
b. After the action taken under Article 7.4.a, for the first two illegal moves by a player
the arbiter shall give two minutes extra time to his opponent in each instance; for a
third illegal move by the same player, the arbiter shall declare the game lost by this
player. However, the game is drawn if the position is such that the opponent cannot
checkmate the player’s king by any possible series of legal moves.

For rapid play:

c. An illegal move is completed once the opponent's clock has been started. The
opponent is then entitled to claim that the player completed an illegal move before
the claimant has made his move. Only after such a claim, shall the arbiter make a
ruling. However, if both Kings are in check or the promotion of a pawn is not
completed, the arbiter shall intervene, if possible.

For blitz:

c. An illegal move is completed once the opponent’s clock has been started. The
opponent is entitled to claim a win before he has made his own move. However, if the
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opponent cannot checkmate the player’s king by any possible series of legal moves,
then the claimant is entitled to claim a draw before he has made his own move. Once
the opponent has made his own move, an illegal move cannot be corrected unless
mutually agreed without intervention of an arbiter.

https://www.fide.com/FIDE/handbook/LawsOfChess.pdf 

Actually I didn't use chess cloak so what rules does that come in? 

#5
Yes, "once" = "after".
Thus:
in classical 2 illegal moves allowed, 2 minutes extra time for opponent.
In rapid arbiter decides i.e. 0 or 1 or 2
In blitz 1 illegal move = loss.

#6
Without a chess clock the classical time control applies.

#9
c. The players must handle the chess clock properly. It is forbidden to punch it forcibly,
to pick it up or to knock it over. Improper clock handling shall be penalised in
accordance with Article 13.4.

13.4 The arbiter can apply one or more of the following penalties:
a. warning
b. increasing the remaining time of the opponent
c. reducing the remaining time of the offending player
d. declaring the game to be lost
e. reducing the points scored in the game by the offending party
f. increasing the points scored in the game by the opponent to the maximum available
for that game
g. expulsion from the event

Was it a tournament game?

Normally, they announce if games are going to be rated or not and what rules are being followed.

If they didn't make any announcement and you didn't use clocks-- did you keep the score? -- it was likely not a rated game and strict enforcement of tournament rules might not apply. (Illegal moves would still be illegal, however.)

In any event, even if it was a rated game, you can't go back the day after and get the result changed.

#12
"6.2 a. When using a chess clock, each player must make a minimum number of moves or
all moves in an allotted period of time and/or may be allocated an additional
amount of time with each move. All these must be specified in advance."
This implies other FIDE Laws of Chess even apply when not using a chess clock.

It was a chess school selection for tournaments so I was playing with my opponent without a chess cloak but following rules and accidentally moved a knight which was protect my king from check. It was an illegal move and my opponent said I lost because in a chess game there is only one illegal move and my teacher said like that but I when I went tournament it is two. So I needed to know which is right? So that I can tell my my teacher.The scoring are not registered. 

I see no ambiguity. It does mean "after".

#17
The wording "once" makes sense: it means immediately after, not a week or a month after.

#14
The FIDE Laws of Chess apply even without a clock.
As there is no clock it is neither rapid nor blitz.
Hence 2 illegal moves allowed.

#19
The problem with 'after' would be that you could claim some moves after or even hours or days after. The meaning of 'once' is clearly immediately after.

#22
In blitz an illegal move is an immediate loss. The reason is clear: in blitz an unnoticed illegal move can get a huge advantage, so when noticed it should meet severe penalty. A strong blitz player once pulled a bishop in a drawn opposite colored bishop ending over a long diagonal to a square of the opposite color and then proceeded to win the endgame. 

#21
"A player must stop his clock with the same hand as that with which he made his
move."
"the king is transferred from its original square two squares towards the
rook on its original square, then that rook is transferred to the square the king has
just crossed."

You didn't say if you had made any previous illegal moves. 

Therefore, I don't see how the number of illegal moves even comes into question.

Therefore, unless you left something out, your opponent was wrong. Under the rules quoted above, the first remedy is to return to the previous position. 

For classical time control:

7.4 a. If during a game it is found that an illegal move, including failing to meet the
requirements of the promotion of a pawn or capturing the opponent’s king, has
been completed, the position immediately before the irregularity shall be
reinstated. 

It should not have resulted in an automatic loss.

#24
Maybe you should write to FIDE about the wording.
"subsequent to" seems less appropriate as the FIDE Laws of Chess are also meant for players and officials not proficient in English. "after" or "immediately after" might be better than "once".

Twice, but in my opinion game should be declared immediate loss after first illegal move is made