"But how does a real morpher exactly work?"
Do you understand basic assembly?
inc eax;
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add eax,1;
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add eax, 3;
sub eax, 2;
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add eax, 10;
sub eax, 9;
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sub eax, 5;
add eax, 6;
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all are equivelent to myAge +=1;
So you get the same final result (eax increases by 1), but the code is different. If an anti-cheat is finding your hack because it scans for it in memory, you can use this to "change the code", but the "new code" does the same things as the old.
It's more complex than that, but that's the basic idea.