Plug-in effects and processors are used in conjunction with Sequencing and Recording programs (mostly). Many emulate what were classic hardware effects, processors and amplification from the past, while others have become cutting edge components in their own right (eg Antares AutoTune).
They are used while recording individual tracks as “inserts” or overall effects/processors as “sends”. They are also used in mix-down, post production and mastering the final recording.
Use is mainly for senior secondary where VET, Music Technology, Audio Design and similar curricula are available as well as tertiary courses.