The easiest method is not specific for WFS layers, but can also be applied to your own feature layers. It concerns the addition of a definition query. A definition query contains several clauses that are written in the SQL syntax. Multiple definition queries can be created for one layer, but only one can be active at the exact same time.
To add a definition query on a WFS layer in ArcGIS Pro, you must first add the WFS through Connections à New WFS Server. The WFS will then be added to the Servers folder in the Catalog pane. Next, choose one of the layers and add it to your folder in ArcGIS Pro. Once the layer is added, right-click it and select Properties. There you will find the Definition Query tab, where you can add multiple definition queries. To filter on the city of Ghent for the WFS layer of the Flemish Government, you create the following query: «Where NAAM is equal to Gent».
However, this first option has the disadvantage that the filter is only applied after the WFS has been added to ArcGIS Pro. If we are working with large datasets, we obviously want the filter to be applied as soon as the connection with the WFS is set up, in order to avoid having to add layers with large amounts of data. Similar to communicating with the WFS via the URL, we can add specific parameters to visualize solely a subset of our data in the WFS.