iWrite is a word processor.
Apart from the common features such as headings, formatting (bold, italic, etc.), tables, lists, etc. iWrite provides the possibility of using complex mathematical formulas and symbols such as integrals, fractions, matrices, special characters (Greek alphabet, mathematical symbols, etc.) and many more.
iWrite is based on the LaTeX-typesetting system. While editing you see an instant preview instead of complicated "code".
In addition you have the possibility to upload PDF files to your device in order to read them.