Why does Fiji have Hindi as an official language?
Apparently Hindi is an official language in Fiji
I've heard about the British exporting (?) people from India but did that many go that's an important language
The British had many sugar plantations scattered throughout their colonies, including on Fiji. After slavery was abolished in the British Empire in the 1830's, the British turned to indentured Indian laborers as an alternative source of labor. About 2 million Indians participated in the program. Ostensibly an Indian laborer would sign a five-year contract to work on a plantation somewhere else in the British colonies, and later to the colonies of other European powers. This lasted from the 1830's to the 1910's. The system was rife with abuse, such as poor working conditions. While some indentured laborers decided not to return home, others were not allowed to go home. Thus Fiji, the Caribbean, and several other parts of the Empire got large Indian populations. You can read more about the system here: https://en.wikipedia.org/wiki/Indian_indenture_system.
Trinidad and Tobago, Guyana and Suriname, apart from their official languages have a large number of speakers of a dialect normally known as Caribbean Hindustani. It's not really the same as Hindi spoken in India, and although very similar, it is not easy for speakers of the two languages to understand each other. The same applies to Fiji Hindi, which has many differences from the Hindi spoken in India.