Apply for jobs, get a job offer. Then employer pays $1k and proves that no Canadian or PR could be hired, only you. Takes months to process and sometimes refused. Then if you get LMIA, then you apply for a closed work permit. The process can take up to a year so few employers go through the process.
You apply for jobs on Canadian job sites. Most employers will not respond because you don’t have work authorization. Most people don’t find jobs and immigrate to Canada through economic immigration programs like Express Entry. This program is based on your age, education, skill and language abilities.
Getting a job with LMIA is very difficult. Look at immigrating through Express Entry. It is based on your age, education (need assessments), language and work experience.
There are very few jobs for fashion designers in Canada so unless you are a very well known designer internationally it will be very difficult to get a job offer and a work permit as a fashion designer in Canada.