My iPhone says network is locked

See this instructions in order to remove the network lock

1. Only your network provider can unlock your iPhone. Contact them and request an unlock. After you've submitted the request, it may take a few days for the process to be completed. Contact your network provider to check the status of your request.
2. After your network provider has confirmed they've unlocked your iPhone, follow the steps below. 

If you need to activate an eSIM from a network provider other than your current network provider

Find out how to set up an eSIM on your iPhone

If you have a SIM card from a network provider that's different to your current network provider

Follow these steps to finish unlocking your iPhone:

1. Remove your SIM card.
2. Insert the new SIM card. Your device will activate.

If you don't have another SIM card to use

Follow these steps to finish unlocking your iPhone:

1. Back up your iPhone.
2. After you've made a backup, erase your iPhone.
3. Restore your iPhone from the backup you've just made.