Start a new project in Illustrator or open the project in which you want to create a dotted line.
Open a new project by clicking Create new... on the left of the main menu or drag and drop an image onto the workspace.
The stroke window lets you adjust the parameters of your line. You can choose how thick the line is, what kind of shape appears around tight bends, and what we came for—a dashed line effect.
To create a dotted line effect, check the Dashed Line line box in the Stroke Window.
Once you've adjusted your dotted line settings, click away from the line with the Selection Tool to leave the stroke in place.
Congratulations! You've created a dotted line in Illustrator.