How the /particle Command Works
The full syntax is /particle <name> <pos> <delta> <speed> <count> [mode] [target]. Delta spreads the spawn area on each axis — 0 0 0 means a single point. Speed multiplies particle velocity. Count sets how many spawn (0 means exactly one, ignoring delta).
Examples
Ten hearts above the executor.
Five explosion particles, forced visible for everyone.
All 115 particle names are on the Particle ID list.