The application process can vary by country. Generally, you'll need to complete an application form, submit necessary documents (like a passport, photographs, and evidence of financial means), pay a fee, and possibly attend an interview. You can usually find specific application details on the official immigration website of the country you intend to visit.

Points are awarded based on criteria such as age, English language ability, work experience, educational qualifications, and more. The current pass mark for the visa is 65 points; however, this can change depending on the invitation rounds. It's beneficial to aim for a higher score to increase the chances of receiving an invitation.

Some countries allow visa extensions under particular circumstances, while others do not. Generally, to extend a visitor visa, you must submit an application before your current visa expires and demonstrate a valid reason for the extension, such as a medical emergency or significant event. The approval of extensions is at the discretion of the local immigration authority.

Usually, visitor visas do not permit employment or engagement in academic programs in the host country. However, certain countries may allow short courses or cultural exchange programs on a visitor visa. If you intend to work or pursue longer studies, you will likely need to apply for a different type of visa, such as a work or student visa.