There are two sentences:
- I prepare the party for him.
- I prepare for the party for him.
What is the difference between the two sentences in meaning?
"Prepare for the party" means that you didn't prepare the party (somebody else did) and you will benefit from that. "Prepare the party" means that you are the one who is preparing a party others will benefit from.
To prepare is to make preparations or make, prepare for is to make ready for something that has not yet occurred.
Although you can say to prepare a party for someone, normally, one would say: to organize party for someone.
Here is an illustration of prepare for.
"I prepared for the exam by studying hard". [to make ready for something that will happen to me].
"I prepared for the party for him". [to get ready for the party that was being given for him. get ready as in get dressed, for example, or set the table and make the food].
"I prepared a meal for him"=I made him a meal.
Now, it is possible to imagine the use of the simple present as historical narrative: One might be describing a number of past events, including: [On Sunday], I prepare for the party for him by having my hair done and buying a new dress. I order the food and set the table.
So, it can be used as historical present. Narrative present but not in conversation where the simple present is only a habitual action.