Mail app on iPad Pro 2021

Hi hemmz,

We understand that you would like to make a local mailbox in the Mail app on your iPad. The steps below show how to create a mailbox, which is from this article: Use mailboxes to organize email on your iPhone, iPad, or iPod touch - Apple Support

"How to use mailboxes 

A mailbox is a folder that you can use to organize your email. In the Mail app, you can use standard mailboxes — like Inbox, Sent, and Trash. Or you can create custom mailboxes. You can also use VIP and flags to make certain email messages stand out.

Create custom mailboxes

1. In the Mailboxes list, tap Edit in the upper-right corner, then tap New Mailbox.
2. Give your mailbox a name. If you have more than one email account set up on your device, tap Mailbox Location and choose the account where you want to create a mailbox.
3. Tap Save, then tap Done.

You can find your new mailbox in the Mailboxes list under the account where you created it."

Please keep in mind that when creating the mailbox, you have to choose an email account to put the mailbox in. It could be possible that this mailbox may reflect on other devices that you use the email with.

Take care.