Iv managed to make the black shading known as the mask tool however I don't see an option for extracting mask... Not a mac user
That was in version 2.75 part of an Addon: 'Sculpt Tools UI', I think. This Addon is no longer maintained and won't work with modern versions (2.8+) of Blender.
When using for instance Blender 2.83 LTS, you have that functionality built in in Blender.
Go to Mask > Mask Extract:
After pressing OK, you get a new Mesh from that Mask:
Pay attention to the fact that you are now in Object Mode with the new geometry selected and there is a SolidifyModifier where you can adjust the thickness, add a Bevel and some more...
You'll have to apply the Modifier before you go into Sculpt Mode for that Object.