static trigger
the icon or window background is clicked or double-clicked
without moving the mouse

dynamic trigger
the icon is dragged and dropped onto another icon or window
background

hold trigger
the mouse button is held down on an icon or window background

There are mainily 3 types of triggers
1> DML Trigger
2> Instead of Trigger written on only view
3> System Trigger

DML Trigger written on table that gets fired on DML events 
like
   insert or delete or update operation
that trigger may fire 
  1> After dml event 
  2> Before dml event these are timings for trigger firing

Instead of trigger written only on view that view is not 
modifiable that also gets fired
 when dml event occurs

System trigger gets fired on system event like 
 before log off or after log on or before shutdown
this trigger  may be written on 
  Database level
  Schema level

Basically there are three types of triggers,

Row and statement triggers
Before and after triggers
Insteadof triggers

Possible combination of these triggers 
Before row trigger
After row trigger
Before statement trigger
After statement trigger

Instead of trigger is mainly for a view.
if we want to write a trigger in such a way that the 
trigger action is to be on underlying base tables of a view,
when an DML statement (insert,update,delete)is issued

1) Action
2) Event
3) Condition