I learned about unlocking process.

If I have at&t services, can I stop before the unlocking procedure of anysim application
install step?

That is, Can I put my old at&t sim card right after paycay steps?

If I do not need to use "anysim", does it mean I did not unlock iphone even though I bypass the activations?

I have no plan to add data plan as well.

Thank you

You realize that your question doesn't make any sense?
If you have "official" iPhone AT&T services, why would you want to unlock the phone? If you want to use your old "unsupported" AT&T SIM in the iPhone, you need to unlock the phone. If you have an "official" AT&T iPhone subscription, activation is no issue.
Of course you can activate the iPhone without the need to unlock it.

Sorry but I don't understand your question???

Thank you for replying
I do not have 'official' at&t iphone subscription.
I am just going to buy an iphone and want to activate to use "unsupported' at&t SIM.
Do I still need to run "ANYSIM" steps to use "unsupported" at&t sim card
after I did Paycay?