Short answers, pulled from the story.
The first episode of the Oh My Goddess! original video animation premiered on the 21st of February 1993. This event marked the beginning of a multimedia phenomenon that would eventually sell over 25 million copies of its source material by June 2020.
Keiichi Morisato is a college sophomore who accidentally dials the Goddess Help Line and makes a wish for Belldandy to stay with him forever. The Yggdrasil computer system grants this wish, creating a contract that binds them together and sets in motion a narrative spanning 25 years.
Divinity in the Oh My Goddess! universe is a profession regulated by strict codes and classifications. Belldandy holds a Goddess First Class, Second Category, Unlimited License, while her sisters Urd and Skuld are Goddesses Second Class, First Category, Limited License who wear power limiters to prevent accidental destruction.
The Oh My Goddess! manga was serialized in Kodansha's Monthly Afternoon from September 1988 to the 25th of April 2014. The series was collected into 48 volumes, with the final volume released as a limited edition box set containing special extras.
The Oh My Goddess! original video animation was licensed for release in North America by AnimEigo. AnimEigo released all five episodes in individual VHS volumes in both English-language and subtitled Japanese-language editions between the 29th of June 1994, and the 31st of August 1994.
Translating the original Japanese title of Oh My Goddess! proved problematic, with fans debating whether to use 'Ah! My Goddess' or 'Oh My Goddess!' approximately 15 years after the first manga was published. Creator Kōsuke Fujishima stated that 'Oh' was closer to his intent, though he acknowledged that titles should make sense within the country of publication.