Unable to find eSIM option on iPhone 13 Pro Max

I'm sorry, I should have told you to tap that model number, which will then reveal another number like A2346.

My initial search based just on that model is it was manufactured for Hong Kong and if it was, it is a dual physical SIM model, which will never support eSim.

There are two primary reasons an iPhone won't have e-Sim:

1. Your carrier doesn't support e-Sim
2. The phone was manufactured for the China/Hong Kong/Macau markets and are dual physical Sim, without the option to use e-Sim

Ask your carrier for help. They have to provision your account for e-Sim service. To be sure though, Open Settings App, tap General, then About and report back the Model Number.

What is the model number in Settings>General>About?

Tap on MLH83ZA/A and another number like Axxxx will appear. Post back with that number