Self-service means helping yourself rather than being waited on. You fetch it, you scan it, you bag it.
The idea began in American grocery stores and reshaped shopping entirely, since supermarkets only work because customers do the collecting. Self-service checkouts moved the scanning to the customer too, which shops present as convenience and customers mostly experience as unpaid work. Petrol stations went the same way. The hyphenated form is standard both as a noun and before another noun.
1nounself-serviceA system in which customers serve themselves.
“The café is self-service after two o'clock.”
Middle English
self
English
self
English, today
self-service
From self- + service. self comes from Middle English self. From Middle English salve, self, silf, from Old English self, seolf, sylf, from Proto-Germanic selbaz, from Proto-Indo-European selbʰ- (“one's own”). 2
Etymology from Wiktionary, CC BY-SA