This depends on every country, I believe. In Argentina (and Mexico as far as I know) we get paid based on project and character “relevance”.
When we record ads we have a legal fee which sets the minimum we should ask for and that number depends on how much many seconds/minutes long the ad is, where it will be used (radio, TV, social media, etc), for how long (a month, six months, etc) and if it is a national or an international project (the more countries it is shown, the more money it’s worth).
Regarding dubbing, the numbers vary according to the type of project (TV show, a movie for theaters, video game, etc) and it will always depend on how much your character speaks. Let’s say I am the leading role in a movie and my character speaks the most, I will get pay US$10 -this number is an example, not a real one). The co-star will get pay US$8 and so and so.
The script is divided into “loops”, every loop has its price…so if my character speaks 130 loops the studio multiplies that value for 130.
At the end of every month, we get paid by the studios or the actors association for the total of projects we worked on.