No option to add esim

_support_apple_ wrote:

Thank you for the information. I bought it from authentic apple store in china mainland. No where it is written that the china models do not have esim.

From: About eSIM on iPhone - Apple Support

From the tech specs, dual nano-SIM. (No reference to eSIM):

And…

透過兩張 nano-SIM 卡使用雙 SIM 卡功能 - Apple 支援 (香港)

And…

如果你的 iPhone 13 mini、iPhone 12 mini、iPhone SE (第 2 和第 3 代) 或 iPhone XS 在香港或澳門購買，請了解如何透過 eSIM 使用雙 SIM 卡。

And…

iPhone 尚未在中國大陸提供 eSIM 功能。在香港和澳門，iPhone 13 mini、iPhone 12 mini、iPhone SE (第 2 和第 3 代) 和 iPhone XS 均提供 eSIM 功能。進一步了解如何在中國大陸、香港和澳門透過兩張 nano-SIM 卡來使用雙 SIM 卡。

You get an iPhone with eSIM.

The dual-SIM iPhone sold in China is dual nano SIM only. There is no eSIM.

The following omits iPhone 15, but the dual-SIM version is the same as iPhone 14:

Using Dual SIM with two nano-SIM cards - Apple Support

Mainland China phone models do NOT offer eSim options. If you need eSIM, return the phone for a refund or sell the phone.

If you had purchased from an authorized Apple dealer in Hong Kong, you might see eSIM options on the phone.

No where? You might want to check this Apple Support document for information about China:

Wireless carrier support and features for iPhone in Asia-Pacific - Apple Support