Most countries offer Work Visas to meet the labour shortage in their country. Often employers find it difficult to fill a particular job locally as they cannot find the required skills in their country. This generally happens with high-skilled as well as trades jobs.
You should have the necessary skills that are in demand in a particular country to get a Work Visa. You should also have the necessary educational qualifications and any certifications that may be needed for the job. You should also have the necessary work experience required for the job.
Some countries may also require you to take a Language Proficiency Test. This is particularly true for English-speaking countries where you may need to take an English Test like IELTS before applying for a Work Visa.