Outlook Mac and iOS Connection to Apple Contacts

[Henry1]

I recently installed Outlook on both devices and am trying to sort out how to manage my contacts. I have about 450 contacts in my Apple Contacts which are stored and synced in iCloud over both devices. Now that I have Outlook, I'm having trouble understanding where I can input new contacts from - Outlook or Apple Contacts? There is no "People" option at the bottom of my iOS Outlook screen - where do I add contacts on my iPhone? If I add a new contact on my Mac through Outlook, is it going into the Apple Contacts file? What's the accepted practice to be sure I have only one contact file and it is updated and maintained in one place?

Thanks, Henry

[#2]

Hello @Henry1 

I've installed Outlook for iOS on my iPhone X and I've added my Office365. 

i'm not able to find my iClould contacts where I try to write an email from Outlook for iOS. 

Could you tell me how we could do this please or it's a restriction? 

I confirm when you enter the whole @ email for the 1st time, Outlook for iOS will remember it next time but It's not able to find it for the 1st time