What is the Shar'i ruling on a husband signing a divorce paper written by his wife while she is in a state of anger, especially given previous verbal divorce incidents in Morocco, and is signing the paper considered a divorce?

No divorce has occurred by your signing a paper written by the wife unless you uttered the words of divorce. A divorce pronounced in extreme anger that causes loss of awareness does not count, but if the anger did not reach this level, then the divorce counts. The general rule is that the husband's word is taken regarding the divorce and its number, but if the wife is certain that her husband divorced her thrice and the husband denies it, then it is not permissible for her to remain with him, and she must escape from him and ransom herself with her money. It is advisable to go to scholars or Islamic centers to clarify the details and to avoid anger.