If you want to manage your contacts in Apple Contacts, make sure you have your UTmail+ account in Internet Accounts syncing Contacts. Open Settings > Internet Accounts and ensure there is a checkmark beside Contacts.
Open Apple Contacts and compare the contact lists within the app (you might have an iCloud list and lists for other email accounts, including your UTmail+ account).
Drag and drop between the accounts to copy them from one account to another.
If you want to export them from Contacts and use them in a different email app such as Outlook or Thunderbird, select the contact list you want to export and go to File > Export > Export vCard. Choose a save location and save the file.