[ElChapoGuzman]

will this work?

new Text3D:label[MAX_PLAYERS];
if(strcmp(cmdtext,"/show",true)==0)
{
label[playerid] = Create3DTextLabel("Whatever u want it to say",0xFF0000AA,30.0,40.0,50.0,40.0,0);
Attach3DTextLabelToPlayer(label[playerid], playerid, 0.0, 0.0, 0.7);
return 1;
}
if(strcmp(cmdtext,"/hide",true)==0)
{
Delete3DTextLabel(Text3D:label[playerid]);
return 1;
}