For :- It is used to say how long something goes on.
Examples
- I talked over the phone for two hours.
- We were on a long trip for a week.
During :- During is used to say when something happens.
Structure: During + noun
Examples
- It rained during the night.
- We enjoyed ourselves a lot during the holiday.
While :- The use of while is the same as During, but its structure is different.
Structure: While + subject + verb
Examples
- I met Rick while I was waiting for the train.
- Harry was playing a video game while his brother was reading a book.
