There is no single procedure. It depends on the type:
(A) Talaq (husband)
Husband pronounces talaq
Observance of iddat period
Attempt mediation (optional but encouraged)
Notice to wife and Qazi may be given
Divorce becomes final after iddat
(B) Khula (wife)
Wife requests divorce
Husband agrees
Wife returns mehr/dower (as mutually agreed)
Divorce recorded; iddat follows
(C) Mubarat (mutual)
Both spouses mutually agree to end marriage
No exchange of allegations
Divorce becomes final after signing the mubarat deed + iddat
(D) Faskh (court annulment)
Wife files in court on grounds like cruelty, impotency, disappearance for 4+ years, etc.