Where: Settings → Company Sending → Email Inbox Capture card.
What's on the card
Toggle: "Capture email replies in PortaPro Inbox"
Default on. It governs both the reply-token Reply-To and the auto-BCC on connected-mailbox sends, as one feature.
Your inbox address
The personal inbound address you can BCC or forward to, with a copy button. It's opaque rather than derived from your slug, so it isn't guessable.
The status pill reports real activity: amber "Waiting for first captured email" until a message actually arrives, then green Active with the date of the last capture. It never claims to be working before it has.
Setup steps for Gmail and Outlook
Including the warning that Gmail's auto-forwarding takes two separate steps. See Email Inbox Capture.
The other two cards on this page
Support email intake and Who sends each email type sit on the same Settings → Company Sending page.
When to leave it on
Basically always. The copy delivered to your mailbox means nothing disappears from it even when capture is on, and you can reply to that copy from your mail client.
When to turn it off
If you want email conversations to be outbound-only and to manage replies exclusively in your own mailbox.