Hello aspirant!

SOF, Science Olympiad foundation, IMO class 11 syllabus consists of 4 sections-
1) section1- Verbal and Non-Verbal Reasoning.
2) Section 2- Diverse sections of mathematics
(Sets, Relations and Functions, Principle of Mathematical Induction, Logarithms, Complex Numbers & Quadratic Equations, Linear Inequations, Sequences and Series, Trigonometry, Straight Lines, Conic Sections, Permutations and Combinations, Binomial Theorem, Statistics, Mathematical Reasoning, Limits and Derivatives, Probability, Introduction to 3-D Geometry. )

3)Section 3- Mathematical Reasoning and Quantitative Aptitude
4)Section 4- HOTS

You can find the detailed information in their official website. Along with this you'll find sample papers and reference books for your practice!
all the best!
https://www.sofworld.org/imo/class-11/imo-syllabus/imo-syllabus-class-11

Dear student,

The sof international mathematics Olympiad is generally consists of 4 sections. Here are the complete syllabus for 11th class :-

Section 1 - LOGICAL REASONING
(Verbal and Non-Verbal Reasoning).

Section 2 - MATHEMATICAL REASONING
( The syllabus of this section is Mathematical Reasoning and Quantitative Aptitude)

Section 3- EVERYDAY MATHEMATICS
(Sets, Relations and Functions, Principle of Mathematical Induction, Logarithms, Complex Numbers & Quadratic Equations, Linear Inequations, Sequences and Series, Trigonometry, Straight Lines, Conic Sections, Permutations and Combinations, Binomial Theorem, Statistics, Mathematical Reasoning, Limits and Derivatives, Probability, Introduction to 3-D Geometry.)

Section 4- ACHIEVER'S SECTION
(Higher Order Thinking Questions)

You'll have to solve for atleast 60 marks to pass the International Mathematical Olympiad. The question papers will consist of 60% questions from class 11 syllabus and 40% from class 10. However, Achievers section will consists of XI based questions only.. Apart from NCERT books, solving previous year papers and IMO sample papers will give you an ample advantage. So practice as much as you can.
Here's the article which you can refer to for a detailed overview:
https://school.careers360.com/articles/imo-syllabus

Good Luck!