Hi, Israa! Great question. I believe that both forms are correct and would work fine. For example, to say "a red or blue car" has the same meaning as "a red car or blue car" or "a red car or a blue car." However, the third format is the most clear. To say "a voice call or a video call" sounds the most formal and therefore would be the most appropriate for a professional interaction. Also, it is not necessary to use a comma after "please." While not incorrect, the use of the comma in this context emphasizes the importance of the request. This does not seem to be your intention. So, in my opinion, it would be best to omit the comma. Good luck with your interview! Your English is great and I am sure you will do very well. :)