Firstly you need to meet the eligibility requirement for the country or the respective territory of the citizenship & under the pool you are applying. Some countries allow you to use once, where others will let you go the application twice, but under a different program altogether. You need to check your country to find out what programs are generally offered for you to quality.
Even if you are given an ITA or an invitation to apply, you cannot participate more times than the respective country allows. Be sure of reading all the documents along with the requirements.
Working Holiday-
This program is for all those who are travel buffs!! This allows you to work temporarily while you are on an extended vacation that can last a couple of years.
This is your ideal category if you do not have a job offer before arrival. If you plan to work with multiple employers and want to work in more than one location, this plan is tailored. If you are planning to earn money while you travel, this is the program for you.

For the young professionals-
This program will allow you to gain Canadian professional work experience to enable an individual to compete in the broader global economy. This is got to be an excellent route for you to take if you already have a job offer in Canada that will allow you to contribute to your current professional development.
You can plan to work for the same employer in the exact location for the overall length of your stay in Canada. You need to know this category is paid and not self-employed. If you are applying for any of these programs, you need to get your documents together immediately. It is mainly because some of these documents can take months to get together.