This is the Golden key that opens the Canadian door. It is required at all the different streams of obtaining a Canadian Permanent Residence.
The IELTS result determines your progress especially at the express entry and Provincial level.
In the IELTS test, your knowledge and fluency of Reading,  Writing, Listening and Speaking are tested. 
The IELTS test result determines to a great extent one’s CRS score.
With the recent upsurge of the CRS score, you are required to make an 8 and above especially for those without a masters degree.
You will need two to three months of intensive study as adequate preparation to ace the IELTS test. Although some candidates have made good results with less number of months of study. 
Preparing with a good practise material is key.
How prepared are you for this test? You can share your challenges and strength.