Shapes, lines & the Pen
Effects and appearance
Select an object and expand Effects in Properties. Use + to add a shadow or blur. A shadow has color, horizontal and vertical offset, blur, and spread controls. Blur has a strength control. Adjust one value at a time so you can see which change improves the result.
Each effect row has a visibility button. Turn it off to compare the object with and without the effect, then turn it back on or remove the row. A hidden effect stays in the design until you delete it.
To reuse a finished look on another object, choose Edit → Copy appearance, select the target, then choose Paste appearance. The shortcuts are ⌘/Ctrl+Alt+C and ⌘/Ctrl+Alt+V. This copies the look without duplicating the object itself. If many objects should stay linked as the look evolves, create an object style instead.
Effects can change print output. A blur or shadow may cause part of an object to be rasterized; a spot ink in that area can lose its separate plate. Review preflight checks and the proof preview before sending the file to a printer.