Please tell me how to tone an image drawn in grayscale for a manuscript.

You can tone a grayscale image from [Effect] → [Tone] in the layer properties.
Even if the expression color is color, you can tone it with the same procedure.

1. 1. Select the layer you want to tone.

2. If you select [Effect] → [Tone] on the layer property palette, the canvas drawing will be displayed as monochrome halftone dots.

If you put the layers you want to tone into a folder, you can tone multiple layers by applying [Tone] to the folder.

* When exporting a manuscript with toned folders, the images are integrated and exported to maintain the toning.