how to create a new mailbox

I want to collect receipts from my inbox on my iPad to a new mailbox, called Receipts.

I tried following instructions but they don’t work.

I see a screen with Inbox, Outbox and Mailboxes: Drafts, Sent, Trash.

I tap Edit at top of screen.  I get Mailboxes: Mailboxes: Drafts, Sent, Trash- but there is no way to add a mailbox; the only option is Done.

What to do.

Thanks,

Owen