How to add Newsletter optin to a checkout step in the shippingAddress block

[RomInfine]

Hello everyone, I start with Magento2. I wish to add an optin newsletter during the purchase process( at the time of encoding the delivery address).

I think we need to update checkout_index_index.xml by overiding him in my theme

but my knowledge ends there. Would someone kindly please explain to me how?
thank you

[karenlovem]

Hi Rominfine. Did you ever receive an answer to your question? I have seen Magento 2 sites with this modification but not sure how it's done. Thanx!