Yes, the iOS 13 Memo app has built-in handwriting recognition. Although it does not support all languages / character types, it can be used conveniently even in a Japanese environment depending on the device.
The handwritten character recognition function of the "Memo" app means that the first line of the handwritten text in the drawing function is used as the headline. In sentences entered with the software keyboard, the first line automatically becomes the heading, but the function is the same.
However, only some character types such as alphabets (uppercase / lowercase), Arabic numerals, and kanji are automatically recognized. Kanji is recognized with considerable accuracy, but hiragana / katakana are not covered, so sentences with kana are not recognized correctly. Even in alphabets and Arabic numerals, the part considered to be the second and subsequent lines is ignored.
Memo recognized as handwritten characters is displayed as "Handwritten memo" when displayed in a list, and the handwritten characters are displayed as thumbnail images at the right end. At first glance, it can be seen as a handwritten memo, so it can also be used for the purpose of making the existence stand out.
Since handwritten characters are treated as figures, the other parts can be used as ordinary memos. Content such as text, tables and photos entered with the software keyboard can be included in the same memo, so you don't have to handwrite the entire memo.
The recognized handwritten characters will be searched. Not only the search field of the "Memo" app, but also the target of Spotlight search (search field that appears when you flick the appropriate position on the home screen downward), so you can use it as a practical headline that is not just a decoration.