If you need to put countless small circles in a drawing, take a rectangle as an example, then you can draw circles on two adjacent corners of the rectangle, then use the "interactive reconciliation tool" to form a row of circles, then use the "+"key on the keypad to copy in situ, then use the up, down, left and right keys to move your group of circles to the appropriate position, and finally press Ctrl+D to copy. But if you want to fill an irregular figure, then this method will inevitably produce a circle outside the figure you are filling. In this case, I suggest you fill in a rectangle on it, weld all the circles after filling in, and finally cut off those redundant parts with a plastic surgery.

This is to fill graphics with graphics.

But if you just want to get a beautiful pattern filled with small circles, you can directly use the interactive transparency tool, select a two-color pattern in the property bar, and then find a circle pattern in the first transparent picker and adjust the size appropriately. Of course, the circle is not very regular, but it is beautiful.