Phiếu Luyện Chữ A4 is an Android app developed by Nguyen Tien Lam, designed for students and learners of Vietnamese who want to improve their writing skills. The app allows users to create their own exercises by typing in letters or phrases, and it also offers pre-made exercises to help users practice their writing.

The app is perfect for teachers, parents, students, and even foreigners who want to practice words and Vietnamese. It offers a range of features, including the ability to enter sample paragraphs, sample poems, and create advanced writing exercises. Additionally, the app provides support for creating basic brushstrokes such as crocheted lines, curved lines, alternated strokes, and tight strokes.

One of the best features of Phiếu Luyện Chữ A4 is the ability to create a PDF file of the exercises, which can then be printed directly from the phone via a wifi printer or shared on other devices for printing. The app is free to use and compatible with Android 9.0.