Different countries have their requirements. If you are a citizen and traveling to Australia you will not need a visa, but if you live more than few weeks, you may need some sort of permission, so it is best to check with your embassy for each country you plan to visit. You need to have a passport that is valid for 6 months after your visit.
If you want to stay in one country for more than 3 months, you will likely need a tourist visa. Work visas may allow you to anything from short to long stay and will allow you to travel the country to 12 months, but does not allow you to work. If you are planning to go to Australia to get your application as soon as possible as it can be a lengthy process. To know more about work visa visit https://www.australiamigrate.com/visa-types/employer-sponsorship-visa/.
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Your visa will be the only country to which you are traveling, so if you want to go elsewhere, make sure you meet the requirements. Pay close attention to the validity of the application, so make sure it will last the duration of your trip. You can only country in which the visa is valid. In some countries, it is possible to extend the visa, but it can be tricky, so make sure you have a number of the embassy sent to your phone!
It is illegal to work on a tourist visa and the consequences can range from fines to imprisonment, so it's not a good idea to get your visa confusion. So remember, when using paid work requires some kind of work visa!