latex4technics - Online LaTeX editor with autocompletion, highlighting and 400 math symbols.

Google Docs - Create a new document and edit with others at the same time -- from your computer, phone or tablet. Get stuff done with or without an internet connection. Use Docs to edit Word files. Free from Google.

Lagrida Latexeditor - Lagrida Latexeditor is an all-in-one website that lets you edit, write or check the authentication of your mathematical equations or symbols in a decent manner without any hassle.

Adobe Acrobat DC - Make your job easier with Adobe Acrobat DC, the trusted PDF creator. Use Acrobat to convert, edit and sign PDF files at your desk or on the go.

Hostmath - Hostmath is a user-friendly mathematical symbol or equation editor that provides you an opportunity to edit your entire difficult equation in seconds.

Wondershare PDFelement - All-in-one PDF editor