▼офіційна довідка

https://helpx.adobe.com/illustrator/usi … encil_tool

звідти написав:

Draw closed paths with the Pencil tool
Select the Pencil tool.
Position the tool where you want the path to begin, and start dragging to draw a path.
After you’ve begun dragging, hold down Alt (Windows) or Option (Mac OS). The Pencil tool displays a small circle (and, in InDesign, a solid eraser) to indicate that you’re creating a closed path.
When the path is the size and shape you want, release the mouse button (but not the Alt or Option key). After the path closes, release the Alt or Option key.
You don’t have to position the cursor over the starting point of the path in order to create a closed path; if you release the mouse button in some other location, the Pencil tool will close the shape by creating the shortest possible line back to the original point.

Може у Вас альт не працює?

в мене все працює без ніяких клавіш

FakiNyan, підкажіть, будь ласка, які у Вас налаштування в Pencil Tool Options?
Ось як у мене:

▼Прихований текст