Hi Seema,

Glad to know about your interest in PRMO and wish you all success. The syllabus is same for all who write the Olympiad and is a little difficult and sophisticated. The main topics are algebra, geometry, integers etc. You can find the syllabus in detail here-

https://school.careers360.com/articles/prmo-syllabus

You need to practice many sample papers, refer to good books so that you are able to qualify for next rounds.

All the best!