I think you are being confused with the digital engineering terms that are used for visual CAD design. These are standard names used for all CAD system.
The constraints are just visual locks to help make a drawing into a solid shape. You can draw a rectangle and “extrude” to create the 3rd dimensional shape of a cube and never realize that there are hidden constraints in plain sight to you probably never realized…especially if you drew the rectangle with exact dimension like in the photo (using a width of 10mm and a hight of 6mm)
The app creators intentionally did not clutter the page with big icons or words so that the app could calculate the math behind make a drawing into a 3 dimensional object. They used penny tiny clues to indicate what is going on
All the subtle clues are selectable and deletable.
But some relationships between the joined lines are just easier to completely delete and redraw, rather the zoom in and try to individually change a line lock
if a section you draw does not turn blue to extrude, then they are not “coincident” (or touching/ locked together) simply enter the drawing and DRAW a line through the object to find the misconnection in the drawing
remember… all items are deletable (except purple indicators), even dimensions. All these things “lock” a shape exactly how it’s needed.
It took me a while to get the hang of what “constraints” to what, and in what order you have to select items to get them to “lock together” how you want.
Youtube is your friend.
https://www.youtube.com/results?search_query=shapr3d+constraints
Once you learn this skill, you can use ANY 3d CAD modeling software. they ALL use the same names, icons, and what they do in relation to each other