@Ebin 

Look here:Configure ESIM

"Configure ESIM
Supported iPhone models can save an ESIM digitally provided by your mobile operator. If your mobile phone provider supports either the provider activation or quick transmission for ESIM, you can switch on your iPhone and follow the instructions to activate your ESIM during the configuration.
If you have already completed the configuration, you can carry out any of the following steps:
ESIM provider activation: Some mobile phone providers can assign a new ESIM directly to your device. Contact your mobile phone provider to initiate this process. Tap on the message "Complete configure the mobile phone" when you get it. Choose "Settings"> "Mobile Funk" and tap "Configure mobile phone" or "Add ESIM".
ESIM rapid transmission: Some mobile phone providers support the transfer of a telephone number from your old to your new iPhone without having to contact your mobile phone provider. Make sure that you are registered on both devices with your Apple ID or make sure that your old iPhone is nearby, is unlocked, iOS 16 or newer is used and Bluetooth is activated on the device.
Select "Settings"> "Mobile Funk" on your new iPhone and tap "Configure mobile phone" or "Add ESIM". Then tap on "Transfer from iPhone nearby" or select a phone number. Follow the instructions on your old iPhone to confirm the transmission.
Note: As soon as the phone number has been transferred to your new iPhone, it no longer works on your old iPhone.
Scan a QR code from your mobile phone provider: Choose "Settings"> "Mobile Funeral" and tap "Configure mobile phone" or "Add ESIM". Then tap on "Use QR code". (You may first have to tap "Further options".) Position your iPhone so that the QR code appears as part of the camera, or alternatively enter the information manually. You may be asked to enter a confirmation code from your mobile operator.
Translated from another smartphone: If your old smartphone is not an Apple iPhone, you have to contact your mobile phone provider to transfer the telephone number.
Activate service in the app of a participating mobile phone provider: Open de App Store, invite the app of the mobile phone provider and act more and the mobile service with the app.
Note: If you are asked to do so, connect your iPhone to an available WLAN network or mobile network. An internet connection is required for the ESIM configuration."

When you need a eSIM from the Telekom:

"In a few minutes you can change your SIM card format from the "classic" SIM card to eSIM and vice versa. Please log into your customer center and then proceed as follows:

Contract details > My SIMs > Settings > Security check > Change SIM > Change SIM card type > Next > Make your SIM selection > now please follow the further instructions

Note: Legitimation via an SMS code ( mTAN ) is required for the security check. The SMS can only be sent to a cell phone number that belongs to your contract account - i.e. if you see several cell phone contracts in your customer center. If you do not have another number to choose from, please contact our customer service."

I hope that helps you