PhD online interview I am invited to an online interview for a PhD position.
Actually, it is my first time.
What are the contents of the interview?
What issues are usually discussed in these interviews?
Am I supposed to represent a proposal in the context of research, at that time?
Which parameters can increase the acceptance chance?
I work in a program for computational science, and we do online interviews with all of the qualified candidates for both our dual-degree (master's-PhD) and doctoral programs.

Because we are a rather broad program, we tend not to favor "quizzes" that test knowledge. Instead, we are looking for things like:


Ability to communicate in English 
Enthusiasm for computational science (many people think we're a computer science program, instead of a computational science program!)
Match for the research interests of one or more of our institute members (particularly for dual-degree candidates)
Previous experience in computational science
Evidence of teamwork and ability to fit our program


There's no real way to "game" the system, at least in my interview, unless you want to invent an entirely new personality for yourself. That's because most of my questions are free-form after the first few, and will try to explore the answers you've given in greater depth. For instance, if a candidate expresses an interest in fluid mechanics, I'll ask what they've done, what makes it interesting, what they'd like to do in the future. If someone happens to express interest in my area (computational materials), things will go in yet another direction altogether. 

The best advice is be yourself. If you try to come off as someone you're not, that will likely show up during the interview.