How to get OpenVPN details from macOS to iOS
Assuming I understand your question correctly, you can use iTunes on the MacBook to transfer the profile you're using into OpenVPN on your iPhone.

Broadly speaking, you need to:


Download and install the OpenVPN app from the app store onto your iPhone
Locate the OpenVPN config file (it should have a .ovpn extension) you downloaded on your MacBook so you know where it is
Connect your iPhone to your MacBook
Launch iTunes
Select your iPhone (within iTunes)
Click on Apps on the left-hand menu
Scroll to the bottom in the main window (on the right-hand side) and click on the OpenVPN icon in the Apps box 
Drag and drop the OpenVPN config file (the one you located at Step 2) into the OpenVPN Documents box
Click on Done
Open the OpenVPN app on your iPhone
You should now see the new certificate listed
Click on the green + sign
Enter your username, password etc
Tap on the Save toggle


Now when you want to connect to the VPN from your iPhone, just tap on the toggle that appears below the Disconnected label. You should be connected shortly thereafter.