Difference between exams and exam

Hi teachers,

The students will sit their exams/exam in June. What’s the difference?

Many thanks.

exams - plural
exam - singular

Thank you, Madam BN.
1= Means they will have more than one exam papers?
2= Means they will have only one exam paper?

2 does not necessarily indicate that they will have only one paper. It indicates that they will have only one exam.
Sometimes a single exam might require a person to sit two separate papers (at two separate times). The marks are then combined to find the single exam result…

Thank you, Madam BN.

Can I also use “examinations” in place of “exams”?

In my country, when we sit an annual exam, we have 5 or 6 or more different subjects. In this case, I must use “exams”, right?

Different subjects are usually for different exams.
Exam/exams are just shortened forms of the words examination/examinations.