The SIM card

It has to be on the right side. Its the only place an iPhone 6 has it.

Below the power button:

Remove or switch the SIM card in your iPhone or iPad - Apple Support

Can you take a picture of the right side of your iPhone?

It is hidden on the side of the phone and you will need the pin that came with the phone or a paperclip to add/remove a sim.

You can do so with the steps here: Remove or switch the SIM card in your iPhone or iPad - Apple Support

That will show a diagram of the sim-slot, how to take it out and it should help! :)

Have a good day!

Look again.

It is on the right side...