Question : How do I set the preheader text in Mailpro?

Open your campaign in the Mailpro drag-and-drop builder and look at the right-hand panel: under General settings → Message you will find the preheader field, directly below the internal message name. Whatever you type there is the preview text inboxes show after the subject line. Leave it empty and the inbox takes the first text it finds in your email instead, which is usually "View in browser" or "Unsubscribe".

Where the field is

1. Open the campaign in the builder.
2. In the right-hand panel, open General settings, then the Message section.
3. Fill in the preheader field, the one whose hint reads "Preview text shown after the subject in the inbox". In the English interface it is labelled Preheader (preview).
4. Save the campaign.

Do not confuse it with Name (internal) just above it. That one is your own label for the campaign and no recipient ever sees it.

A preheader only works as a pair with the line above it: see how to write a good subject line.

How long should it be?

Aim for 40 to 100 characters, and put the words that matter in the first 40, because phones show less than desktops. Under 40 characters the inbox may fill the remaining space with the next piece of text in your email. Over 100, the end is cut off on most phones. The Mailpro guide to email preheaders goes through the length ranges with examples.

What to write in it

Treat the preheader as a second headline, not a repeat of the first. The subject line makes the promise; the preheader adds the detail that did not fit, the deadline, the discount, the name of the report. Repeating the subject word for word wastes the only other line you get in the inbox, and leaving it blank hands that line to your unsubscribe link. Increasing your open rate covers the other levers that move the same number.

For the definition on its own, see email preheader.