I am doing the scanning of an identity document, but when it does it adds two zeros to the beginning of the document in column (N° Cédula),

I am trying to remove those two zeros with the SUBSTITUTE formula but it also removes the two zeros that are after the “8”, I tried with the formula LEFT tell it to only remove the first two zeros from the beginning but it doesn’t work, do you know how I can improve the formula?

Try using just this as your expression:

NUMBER([N° Cédula])

I already tried but it does not remove the two zeros that are at the beginning

Expression Steve showed should work.
I suspect you set the field data type with this expresssion (VC) to text instead of number type.