You can add segments to a path with the Pencil tool, regardless of which tool was used to draw the path, and whether or not the path has an applied brush stroke. If a path does have a brush stroke, you can also add to it by using the Paintbrush tool.
Ways to add segments to a Path
1. Add anchor points
2. Use Pencil tool
3. Use Paintbrush tool if the path has brushes strokes
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