Since speaking from experience is most accurate, most of this post would be based on my application to Yonsei University Underwood International College.
Based on experience (of my own), the application deadline for Fall Semester is late March to mid April. Except the Yonsei University Wonju campus that had a 8th March deadline. For us Singaporeans it means that we have about 1 month in general to apply for the university after the release of A Level results (usually on the first Friday of March).
Common documents required:
1. Application form with passport size photo attached
This is where you fill in your name, age, etc.
2. Results Slip
It can be your GCE A Level, IB, SAT I, SAT II, etc results, an exam that you have taken as a major exam at the end of 12 years of schooling. Some may require your GCE O Level/IP results as well.
3. High School (Junior College equivalent) and/or Middle School (Secondary School equivalent) transcript
In the Singaporean context, JC transcript would be your Prelim transcript. Secondary School transcript would be the O Level cert or IP Results Slip (remember to also submit the explanatory letter about IP issued by MOE as well!) Some may require you to submit your testimonial too!
4. Teacher’s Recommendation (1 or 2 depending on the school’s requirements)
Most universities would have a form for you to get your teacher to fill in. The teacher is expected to seal up the letter in an envelope and it is best if he/she signs on the flap to ensure that it has not been opened. If the confidentiality of the letter is compromised, the letter may be considered invalid. So even if you’re dying of curiosity to know what your teacher think of you, please refrain from opening the envelope and reading it! Universities would encourage the teachers to send out the letter once they’re done with it but as a student, you should either provide your teacher with the stamp or mail it out yourself. You owe your teachers a lot for their guidance, and now they’re helping you write recommendations, so it’s only right that you mail it out for them. Some schools may have their own set of protocols, so please also check with your school if you’re unsure. Also remember that your teachers are also busy with their own stuff and teaching your juniors, so please don’t expect them to be able to complete in a day! Give them about 2 weeks to complete it, if your teacher completes it beforehand I’m sure he/she will not hesitate to pass it to you or whatever your school protocol is ^^