Go to Settings > Cellular/Mobile > Add Cellular/ Mobile Plan.
Tap on Enter Details Manually.
Enter your SM-DP+ Address and Activation Code.
Tap on Add Cellular Plan.
Label the eSIM.
Choose preferred default line to call or send messages.
Choose the preferred line to use with iMessage, FaceTime, and Apple ID.
Choose the eSIM plan as your default line for Cellular Data and do not turn on “Allow Cellular Data Switching” to prevent charges on your other line.
Your eSIM has been installed successfully, please scroll down to see the settings for accessing data.