Your question is about the romaji spelling of Japanese kana.

When expressing Japanese in English, its Roman pronunciation must be used. Just like Chinese pinyin, each kana has a corresponding prescribed Roman pronunciation.

For example, ち=chi, し=shi.

The English spellings of Japanese personal names, place names, and trademark names all follow this pattern

For example, Toshiba とうしば＝TOSHIBA

Chiba ちば＝CHIBA

Although you can use the other methods you mentioned when typing, those are just input methods and not the formal Japanese romanization.