Wave soldering is used for through hole, not surface mount, components.
With wave soldering you have a bucket of molten solder that is pushed over the lip of one edge of the bucket. This is the wave. The circuit board is transported over the wave, just touching it. Solder flows to the exposed copper, but not anything else (which is referred to as solder resist in this context - that blue colour is solder resist).
Surface mount would tend to use screen printed solder paste and then a hot oven to melt the paste.
Just a clarification here: you can in fact wave solder surface mount parts, and it's often done. It doesn't work for leadless parts or parts with pins under the package such as BGA and LGA but it can be used, with proper board design, for most other parts, even surprisingly fine-pitch ICs. The parts are glued to the PCB and then passed through the wave. The most common use is for passives, such as decoupling caps, on the bottom of a PCB.
Wave soldering is used for through hole, not surface mount, components.
With wave soldering you have a bucket of molten solder that is pushed over the lip of one edge of the bucket. This is the wave. The circuit board is transported over the wave, just touching it. Solder flows to the exposed copper, but not anything else (which is referred to as solder resist in this context - that blue colour is solder resist).
Surface mount would tend to use screen printed solder paste and then a hot oven to melt the paste.
The Slow mo guys have a video about how expensive cameras are made which covers some of the process: https://www.youtube.com/watch?v=LaqeLrLxYOg