Before you start, you should consider whether you need to improve your written English or your typing skills
Do you need to brush up on your English? Test yourself, try this diagnostic test.
For a useful app for you smartphone, try SpeakingPal.
If you are not an English native speaker, this course on Basic English Grammar is very helpful. You can receive a diploma upon completion.
To participate successfully in online higher education courses, you will need a minimum TOEFL iBT score of 6o, or an IELTS score of 6. For university studies in the U.S.A. you would normally need a TOEFL score of 80.
Here is a TOEFL and IELTS comparison tool.
Being able to type at a normal touch typing speed of 60 words per minutes is a very useful skill. Test yourself here. If you practice 5 minutes per day during a month you will greatly improve your speed. There are numerous typing tutor applications available, both online and offline.
MOOCs, Massive Open Online Courses:
You can download a free online book, Studying a MOOC: A guide by Professor Neil Morris, University of Leeds, UK.
Shorter, practical courses:
Cisco Academy. Use this Academy ID: Camara Education Ethiopia, Cisco Academy, ID 20025931