The category based on purpose includes:

1. **Tourist visa**: Allows entry for tourism purposes, available as single or multiple entry depending on the nature, duration, and frequency of visits, as determined by immigration officers.

Requirements: Various benefits include longer tourism periods up to six months, but possible disadvantages include potential visa rejection and long processing times requiring early planning and financial proof.

2. **Medical treatment visa**: For those seeking medical treatment unavailable in their country or better medical care available in Canada.

Requirements: a valid passport, a medical report, a letter detailing treatment duration and type from a Canadian doctor or hospital, health insurance, proof of financial capability, and a visa application form. Benefits include easier access to treatment and advanced medical staff.

3. **Family visit visa**: For visiting family and relatives in Canada, a temporary visa can be single or multiple entry.

Requirements: a valid passport, an invitation letter from family or relatives residing in Canada, proof of social ties, financial capability, photographs, a visa application form, and a fee payment. Benefits include opportunities to explore Canada and meet family and friends, with an increased chance of acceptance with proper preparation.

4. **Business visa**: Temporary visa for business purposes such as meetings, commercial contracts, or finding business partners.

Requirements: a valid passport, photographs, a visa application form, proof of business objectives, financial capability, national ties, comprehensive health insurance, some medical tests if necessary, and a detailed trip and business activity plan. Benefits include exploring the Canadian labor market and expanding business opportunities, but restrictions apply to working.

5. **Seasonal work visa**: Temporary visa for foreign workers during peak agricultural seasons, known as the Temporary Agricultural Worker Program.

Requirements: passport, photographs, documented job offer in Canada for visa applicant, work permit aligned with job offer before arrival, fee payment, proof of eligibility and national ties, and passing required medical examinations. Benefits include renewal and good income from work in the agricultural sector, but limited health insurance and living conditions in rural areas may be challenging for some workers, and the visa duration is limited to not exceed 8 months.

In conclusion, the visitor visa is a gateway for entry into Canada, offering opportunities to explore the country and sometimes gain financial or business benefits.