Hi Gabriel! To answer fully I would need a bit more information on what you are actually trying to do, and it would be helpful to know what you have already tried so that the advice can be customized, but to begin here are examples/tools that help you to do at least a part of what you are asking.
1. To manage which labels are showing, you can create label classes and use SQL Query to include and exclude values. Eg. class 1 with labels that are in areas not crowded, and class 2 with labels in crowded areas.
2. Bookmarks can be used to zoom in to certain areas that you have saved in a certain scale, but this only works in map view.
3. Visibility range can be established to only show layers and labels when you are zooming in/out within certain scales, eg. between 1:10000 and 1:100000.
Let me know if you need more information on these, and if you're looking for something else, I'll let others chime in.