I would like to ask about mistakes in my letter. ......- are proper names or personal information.
Dear Sir/ Madam,
I am applying for ... at your university at .... academic year. I am currently studying Mathematics and Chemistry on extended level but I would like to write .... exam also from Physics, for which I am preparing unassisted. Is it possible for me to apply for a Foundation Year with ... from physics? I would also ask if there is possibility to apply for a course with and without Foundation Year and what are the requirement for a Foundation Year for ....
Thank you for your time considering questions.
Your faithfully,
......
I think I can clear up the first blue part. The OP is saying that where they have written a string of dots, those dots replace proper names or personal information.
Remember - if you don't use correct capitalisation, punctuation and spacing, anything you write will be incorrect.