Jaenre is short for JApanese-ENglish-REsource. It is a reference tool to help English speakers to work with the Japanese language.
Jaenre Transliteration is based off the transliteration functionality that is used in the Jaenre desktop application.
Transliteration is the process of converting the sounds expressed in one character set into the sounds expressed by another character set. In the case of this app, it converts the sounds as expressed in the Roman (romaji) alphabet into sounds expressed by both the Hiragana and Katakana character sets.
Basic usage involves tapping on the upper text field on the Convert panel to bring up the keyboard. As one types, the conversion to the Japanese characters will occur in real time. Press the Done button to hide the keyboard input. Press and hold either the hiragana or katakana field to bring up the copy menu. Alter the selection bars and press Copy. Switch to another app. Press and hold on a text field to bring up the paste menu. Press the Paste button to insert the text.
Since this app converts sounds, notice that features like auto-correct and spell-checking are disabled.
There is a mapping panel to adjust how the romaji characters are converted.