This app is designed to help you convert Cantonese text into jyutping, which is the romanized phonetic writing system for Cantonese. To use this app, simply type in the Chinese text that you want to convert into the left box and then click on the "convert" button. You will then see the corresponding jyutping for the Chinese text appear in the right box.
Jyutping is a system used to write Cantonese using roman letters. As an example, this would turn 你好 into nei5 hou2. Jyutping is the most popular system, similar to how pinyin is used to write Mandarin. This is designed for Cantonese learners. There are several different romanisation systems for Cantonese but Jyutping is the main one used in Hong Kong, considered the "standard" romanisation. Other romanisations include Lau, Yale and Meyer–Wempe.
This app can be a helpful tool for learning Cantonese or for checking the pronunciation of Cantonese words and phrases. Some words may have multiple pronunciations so for these words, it's possible that the app has the incorrect pronunciation.