it is prohibited to announce someone's death by publishing an obituary. It is, however, permissible to announce the news of his death to his relatives and acquaintances so that they can attend the Funeral Prayer and follow his burial procession. When
Al-Najashy died in
Abyssinia, the Prophet (peace be upon him) informed the Muslims of his death and offered a Funeral Prayer for him.
it is not permissible to attach a notice board on the wall of a Masjid for the purpose of writing obituaries or anything of the sort because Masjids are not constructed for such purposes.May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family and Companions.