GMAT everywhere!

More than 5,900 programs offered by more than 2,100 universities and institutions use the GMAT exam as part of the selection criteria for their programs. GMAT is a computer adaptive test which assesses a person's analytical, verbal, quantitative, reading and writing skills. All these skills are required to study in  Management program, especially MBA. 
Contrary to popular belief, GMAT does not measure Business or management skills but tests the taker in analytical writing and problem-solving abilities, while also addressing data sufficiency, logic, and critical reasoning skills that it believes to be vital to real-world business and management success. 
The GMAT exam consists of four sections: An analytical writing assessment, integrated reasoning, the quantitative section, and the verbal section.^[16] Total testing time is three and a half hours, but test takers should plan for a total time of approximately four hours, with breaks.

Section	Duration in minutes	Number of questions
Analytical writing assessment	30	N/A
Integrated reasoning	30	12
Quantitative	75	37
Verbal	75	41

Speaking more generally, for whatever MBA admissions round you're targeting, your target date for taking the GMAT should be at least two months before your first application is due.

Start preparing soon and you can do it without much trouble. 

For coaching you can try Confluence Educational services.