This is a free online test. It is based on the internationally accepted standard CEFR (Common European Framework of Reference). Your result will tell you which level of English you have and which international exam (Cambridge, IELTS, TOEFL, etc) may be best for you to prepare for.
You can also get a PDF certificate of the level you have that you can use for work and studies.
Select a test and follow the instructions or process.
At the end of the test you will see your results.