How to put the email signature at the bottom in replies?

Nothing is being foisted on anyone. You can readily delete all or any portion of the text in a reply that you wish to. Don’t want the quoted stuff included - fine. Just delete it before hitting send.

What you cannot do is alter the default signature location.

Yes but... “all that quoted text” is not polite to send again. It is supposed to be trimmed down to only that which is pertinent to the reply additional contribution. No matter what revisionist’s try to foist on us the language is still written left to right, top to bottom in chronological order.

What is said first belongs first. What is said later belongs after. Except in email where the effect of conversation may be created by interspersing reply after and between quoted sections.

Consider this: you send me a message with bulk content you don’t expect me to read, then why do you believe I will consider anything you send to be worth my effort?

That Apple foists a misbegotten behavior on iOS users drives many to Android. Reminds me of Outlook where it was once impossible to edit or trim quoted content. May still be, I don’t know, Microsoft lost me forever.

I may have lost something here but go to the Settings > Mail, Contacts, Calendars > Signature and set there the text you want to use.

In iOS mail you cannot change where the signature appears. It will be inserted at the bottom of the current or active reply Section. You cannot change that to be at the bottom of all current and past/reply block text. If that is what you wish, you'll need to cut and paste the signature to where in the message body you want it.

Honestly though, for myself, if you stuck it at the very bottom, after all the quoted previous text, I'd rarely see it. It makes the most sense to me to always put it at the bottom of my current reply block, and that's the convention I've used for decades and most other people I correspond with for work also seem to use.