Recently I have been contacting profs from different research groups about the possibility to work my PhD research in their group. Again, the e-mail I have sent to them only asked if there are open positions in their research group as well as asking for a brief description of the position. I have not indicated that I will 100% apply for the position, for the moment I just want to have multiple choices of my future PhD topics and later decide on myself which of them I will apply to. However, all profs who have replied my e-mail always directly asked me to send them the application documents (e.g. transcripts, CV, letter of motivation, and contact to referees) without giving me the information of which positions they are offering. I have not received all transcripts from the administration office of my current department and also I can't prepare a convincing letter of motivation in only days. Is it indeed a common thing in an application procedure to a PhD program that the prof will not tell you their offered position unless you officially apply for the unknown position? What do they mean when they ask you to provide them those documents, are they only needed to adjust the positions to your background without considering you applying to the program, if so why need a motivation letter and referees? I haven't replied their e-mail, I actually want to say that for the moment I'm merely interested in knowing what positions they have but that seems to make me sound not serious in applying, so I have been holding their e-mail for now. What should I do? Probably it will be different if their location is within reach from my place so that I can probably ask for a personal talk to discuss about the position, but in my case they are from various countries.