Most work with edges is already covered as a subset of faces and vertices. One thing we will explore here is detecting edges with zero length.
These edges appear from a variety of things. When working on a mesh if you extrude then decide you don’t want to extrude, if you don’t undo all the way, edges will remain on the mesh but with no real length. If a cube is scaled flat on any one axis, the edges which were laying along that axis are now of zero length. When correcting n-sided polygons, if two vertices are snapped together but not merged there will still exist an edge with a zero length.
Using Select Constraints Tool
Select > Select Using Constraints Activate your move tool and make sure that All and Next is the Constraint selection. Using the Length tab, activate the option and leave the default min/max at zero. If your Move tool selection locates to anywhere near the mesh then you have edges with a length of zero. To eliminate these edges use Edit Mesh > Collapse