I am a home canner. There are two processes.
Water bath canning, in which jars packed with food are boiled at ambient pressure and thus 100C or slightly less. This is only suitable for high-acid foods like fruit jams, jellies, acidic pickles and some tomato recipes, because the botulism spores are left alive, they have to be kept inert by the acid in the food. Any pot large enough to completely submerge the jars with an inch of water above will do; I use an old stock pot.
Pressure canning, in which jars are boiled in a pressurized vessel that raises the temperature high enough to kill the spores outright. This is the only method that can be used for low acid foods like vegetables packed in water, low acid tomato recipes, meats, soups etc. A pressure canner is conceptually similar to a pressure cooker, but larger to fit several jars, and they operate at higher pressures and temperatures. A pressure cooker is not suitable for pressure canning, a purpose built pressure canner is required.