in time/on time
Both "On time” and “in time” are two prepositional phrases that are somewhat confusing. “On time” means at the planned or specified time; neither late nor early. It denotes being punctual:
Peter wants the meeting to start exactly on time.
Please, try to arrive on time for the programme.
“In time” means with enough time to spare; before the last moment:
The boy would have died if they hadn’t got him to the hospital in time.
It could also mean in the future or eventually:
In time, he will see that life is not a bed of roses.