To blanch corn, fill a very large pot with unsalted water; I recommend a canner because it holds a substantial amount of water. The water will cool down after you add the corn. Because a canner holds such a large amount of boiling water, the water will cool less, returning to a boil very quickly after you add the second and subsequent batches of corn. Once the water’s at a rolling boil, plunge in corn cobs that have been stripped of their husks.
Alternately, use vacuum-sealed bags or wrap each cob in clear cello before bagging and freezing. If what you want is kernel corn, blanch, chill, and dry the whole cob before cutting the corn as kernels. Kernel corn needs less freezer space than corn on the cob - a definite plus! For a fabulous way to husk and cook corn cobs super fast, see the Index for How to Shuck and Cook Corn.
Note: I’m going to assume you want to freeze many cobs of corn; if not, an ordinary large pot will do fine, but will restrict you to working with only a few cobs at a time. Smaller veggies and tree fruits such as peaches or apricots need less blanching time; remove them with a slotted spoon or smaller tongs. Transferring peaches and apricots from boiling to icy water loosens their skin enough that you can rub it right off.