How to snap the origin manually to a vertex..etc

  1. On the top right corner of the 3D Viewport, you have a drop down menu called options. These are the transform options.
  2. Put a tick next to the origin. This will enable the origin to be transformed (moved..etc) like a vertex.
  3. In the object mode, select the origin.
  4. Now with the vertex snap enabled, move the origin towards the vertex that you want to snap it by pressing the G key after selecting the origin.
  5. Thsis should snap it to that vertex.