How are parameters different from filters? This table summarizes the main difference.
Tableau defines parameters as workbook variables like a number, date, or calculated field that allows users to replace a constant value in a calculation, filter, or reference line. While the primary role of filter is to narrow down data, which allows both basic and complex filtering base on specific Order of Operation.
A Parameter is independent of the data source while filters are not. We can see this when we add quick filters on, for example SUM(Sales), show filter and see how filters display exact number of boundaries, derived from data source. With parameters, user can set his own values and boundaries.
A Parameter's scope is at the Workbook level, meaning it can be seen by any worksheet in the same workbook while filters are by default is at the Worksheet level. However we can apply our filters to different worksheets if we want to.
Parameters can be used in calculated fields where as filters cannot be embedded inside expressions.
Filters in form can have multi-select values while parameters are single select base on a list or require user input.
Actions are available for parameters but not for filters. Parameter actions enable changes in your view, by hover, select or menu.
We can recognize these differences more easily as we keep learning more.