You can find the nearest embassy of the Republic of Bulgaria where you can apply for long term (student) visa in the link below:
http://www.mfa.bg/15/findanembassy
First requirement for those who are interested in joining an institute of higher education in Bulgaria is a Diploma or Certificate proving successful completion of the previous stage of education.
If you are preparing to come to Bulgaria as a student then you will need to first apply to a college or university in the country and get accepted for admission to a degree granting program. It is important to make sure that the school that you are applying to is an approved Bulgarian higher educational institution. You will have to be able to show that you have sufficient financial means to cover the cost of your education as well as general living expenses while in Bulgaria. You will also need to submit to a medical exam to prove that you are in good health.
For some countries, depending on agreements between Bulgarian and their governments fees will not be applied while for others there is a fee for issuance of long-stay (student) visa.
Long-stay visa D valid up to one year and the right of stay up to 360 days may be issued to foreigners who commit research or students in training programs for up to one academic year, graduate students or trainees.
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You can expect it to take about a month for the Ministry of Education and Science to look over your application and render their decision on it.
Videos explaining the procedure or to fill the applications. Attach videos using the following tag <&video type="website">video ID|width|height<&/video&> from external websites. Please remove the "&" inside the tags during implementation. Website = allocine, blip, dailymotion, facebook, gametrailers, googlevideo, html5, metacafe, myspace, revver, sevenload, viddler, vimeo, youku, youtube width = 560, height = 340, Video ID = Can be obtained from the URL of webpage where the video is displayed. e.g In the following url "http://www.youtube.com/watch?v=Y0US7oR_t3M" Video ID is "Y0US7oR_t3M".
Once you have been granted admission to a Bulgarian university or college you will need to send you admission documentation as well as the proper paperwork for a long stay visa to the Ministry of Education and Science in Bulgaria. The Bulgarian visas are issued by the Bulgarian embassies and consulates abroad, not at the airports or the land and sea passport control points in Bulgaria.
The second step to study in Bulgaria, after getting acceptance letter is to apply for Bulgarian student visa (D-type visa) valid from 3 to 6 months. Bulgarian student visa can be obtained from any Diplomatic Mission abroad for students fulfilling some requirements. By getting a student visa, you are making sure that you are legally in the country.
Once you actually arrive in Bulgaria you will be issued a Bulgarian ID card with your Type D visa. If you do not have a Type D visa you will not be able to be issued a Bulgarian ID card. This is important because you cannot register as a student at a Bulgarian university or college without a Bulgarian ID card.
http://www.isep.org/students/Placed/handbook_visa.asp?country=8
https://www.mfa.bg/en/pages/109/index.html
More information which might help people.