Vocal techniques are the physical skills required for singing such as posture, breathing, resonance and articulation.

Some points about technique:

• correct and efficient breathing technique is required for singing, especially when singing classical as these singers start a song at 70% lung volume. Speech-like quality which is heard in contemporary singing requires about %40 lung volume (more is used when belting).
• before singing and breathing the singer must first 'set-up' the technique mentally. This means the student should 'hear' the note in their head, set up the articulators (lips, tongue, teeth, jaw) and all necessary technique before the first note is sung.
• technical terms for the body parts singers and singing teachers use (and refer to) are: costal=ribs, mandible=jaw, internal costal muscles=muscles in between the ribs, (well, I found this interesting!)
• learning how to sing in the abstract can be boring for the student e.g. only doing exercises and technique for long periods without singing (applying it to) songs.

I believe technique can be applied to a song soon after learning it. Admittedly, the technique should be isolated and taught to the student until they have  grasped it, but once this has been achieved, they can apply it in the context of a song (which can be different to the context of an exercise)