Open the Phone app
Tap Recents
Tap Edit
Tap Clear
Tap Clear All Recents
To delete a single call, swipe left on the call
Tap Delete
To delete voicemail history, open Voicemail
Delete individual voicemails
To clear Safari history, open Settings
Tap Safari
Tap Clear History and Website Data
To clear Messages history, open Messages
Open a conversation
Tap the contact name
Tap Info
Delete the conversation or individual messages
To clear call history synced with iCloud, turn off Phone in iCloud settings if needed
To remove recent searches, clear Siri and Search suggestions in Settings
To erase all data, open Settings
Tap General
Tap Transfer or Reset iPhone
Tap Erase All Content and Settings