The character [把] or [將] directly placed before an [object] is called 'dispositive marker'. The role of a dispositive marker is to dispose the object.
"我殺了" (I killed) is a phrase with only subject and verb.
To make "我殺了" a complete sentence and explain " who killed whom" we can place the object after the verb and write "我殺了[他]" (I killed him). It is a simple SVO sentence. The emphasis is on the subject and it's action.
Or you can insert [ dispositive marker+object] between the subject and the verb and write " 我[把他]殺了" (I killed him) . The emphasis is on the object that is being disposed by the verb. ('whom was killed by me' is the more important information than 'I killed someone)
In "送走他", [送] is the main verb, [走] is the resultive verb particle that indicate result of the action. The object [他] is placed directly after both.
In "送他走", the object [他] is inserted between the verb, [送] and its resultive particle [走]
Both phrases above focus on the verb
In "把他送走" , the object is being disposed by the verb 送走
The focus in this sentence is the object being disposed by the subject in the method of the verb.
('whom is being sent away' is the more important information than 'the subject send away someone')
In "打他一頓", [打] is the verb, [他] is the object,
This sentence focus on the verb 打.
In "將他打一頓" the object, [他] is disposed by the verb [打]
The focus in this sentence is the object being disposed by the subject in the method of the verb.
('whom is being beaten' is the more important information than 'the subject beating someone')
You cannot use dispositive markers if the verb doesn't dispose the object
For example :
看他一眼 cannot be rephrased as 將他看一眼. - look at an object doesn't change the object's situation (should be 對他看一眼)
回答他 cannot be rephrased as 把他回答 - 回答 is not an action verb that can dispose an object ( should be 向他回答)