Use the Vector Brush Tool to apply vector brush strokes to your design.
Affinity Designer provides an impressive selection of vector brushes for use with your Vector Brush Tool with each category containing brushes of varying properties and characteristics; vector brushes are only available via Designer Persona. As well as using the Vector Brush Tool to apply 'freehand' vector brush strokes to your page, brush strokes can be applied to object outlines and around photos.
A key characteristic of vector brush strokes (compared to raster brush strokes) is that they can be edited using the Node Tool after applying to the page.
Brush strokes are applied to your page using a combination of the Vector Brush Tool, the Brushes panel and the tool's context toolbar.
If you want to save a brush, these can be stored in the panel as a custom brush for future use.