New to iOS. Have some doubts.

Hi everyone

I am new to iOS and recently got my first iPhone.

So I have some doubts..

1) Is there any way to lock application(mail, messages) on iOS or any application which does that(tried searching but couldn’t find one).— something like app lock on android

2) Is there a way to include more recent dialled numbers in the phone app . Like I make a lot of calls and the number of calls that the recents shows is limited . Sometimes due to many calls it does not even show the calls of yesterday

So any app or setting change for this ?

3) Is there any way or app to club all the calls made to and received from a particular person(in recents )?

Thank you all in advance