There are two main types of report filters. The Visualization filter or the chart-level filter applies to each individual visualization on the report page. The View filter or the page-level filter applies to the entire report page and all the visualizations on the page.
The methods to interact with reports are Reading View and Editing View. Each one has different filtering capabilities available, which depend on which mode you're in.
In the Editing View, you can add the page filter and the visualization filter. When you save the report, these filters are saved with it.
In the Reading View, you can interact with the filters you added, but you cannot save their changes. In this view, you can also interact with any page and visualization filters that already exist in the report, but you won't be able to save your filter changes.