Jam and preserves are basically the same thing and the terms are often used interchangeably.
Jam is a mixture made of crushed preserved fruit and sugar — with or without pectin, depending on the pectin content of the fruit. High-pectin fruit will set well once the fruit and sugar have been boiled and pectin is activated. You may need to add pectin to lower-pectin fruit.
The word preserves means fruit that is cooked the same way; the only difference is that the fruit in preserves is often cut into chunks or in some cases whole, whereas jam may have a less chunky texture.
The common fruit/sugar ratio in jam and preserves is 50/50.
Freezer jam is cooked more quickly than conventional jam and stored in the freezer for a fresher fruit taste.