Took it yesterday actually. Once you buy it, Italki will take you to a page, but also send you a message. The instructions on the page are less helpful than the ones in the message, so read that too before proceeding.
You will be asked at the beginning what is your level in English.
The exam is 50% British/ 50% American English
FIrst, about 30 text exercises, 99% of them you choose the answer from a list (like, "here's 3 sentences from a conversation, what does the guy think? Tick one of the 3 options"), often about 'stretched verbs' like "by brush off does he mean he took it seriously, not seriously, etc.", but one exercise is one paragraph where you have to fill about 10 empty boxes with something you will type (like, the sentence has an "as if" in it, but the "as" is cut out, and you need to be able to understand that "as" goes there, and type it). Can be tricky.
Second, about 15 audio tracks to listen to, with a question about the content, you have to pick the correct answer among a list, sometimes you get asked two about the same track. You can listen to the audio only twice. First listening may feel confusing, second will be better.
Sometimes the track pauses without warning, I think it has to do with buffering, so wait for it.
I think a problem with the audio part is that some tracks are really ambiguous, or the question is, so it's not immediate to be able to select the "correct" one, but I felt this only about a couple of them, which I resent (or I will once I get my results).
Natalya, i know nothing about this Italki certificate and how valuable it is with job application... so it is your call to take it or not...
But if you just need to check your level for free you can do it here https://www.efset.org
There are two tests, I suggest you to choose the longer one (50 minutes).
Of course, this test is not as complicated, comprehensive and serious as ITELS or TOEFL are. But it will help you evaluate your reading/listening level. Anyway, it is free.
You will get on-line certificate that you can connect with Linkendin. I don't think any of employers will take this one seriously but it wouldn't go amiss :-) I did it)
And you will be able to see your score on different scales (like TOEFL, ITELS, <a href="https://www.efset.org/english-score/cefr/" target="_blank" rel="nofollow" id="cefr" style="background-color: rgb(255, 255, 255); color: inherit; outline: 0px; outline-offset: -2px; font-family: Arial, sans-serif; font-size: 14px;">CEFR</a>).
Good luck!