?

[edgy matrix]

if its in a command block use impulse
if its in chat, just say it in chat
if its functions use scoreboards to toggle a value so it will only execute once

[edgy matrix]

well which didnt you understand

scoreboard objectives add toggle dummy
execute at @a[hasitem={item=pa:deve,location=slot.armor.head},score={toggle=0}] run particle minecraft:totem_particle
execute as @a[hasitem={item=pa:deve,location=slot.armor.head}] at @s run scoreboard players set @s toggle 1