I like to dimension my sketches from the part’s origin. The only way I have found to do this in Shapr3D is to draw construction lines through the origin and lock them on the three axes. There must be a simpler way in this package.
If there is a planar face which contains the origin point, you could select the face and double tap with your finger to start sketching on that face. The shapes you draw could be linked to the point, if they touch.
I could give you more specific help, if you share a screenshot of what you are trying to achieve.