Auto-fill Your Subject Line with Expand
With the Expand feature, you can insert text into your emails and pre-fill the Subject line — all in one go.
No more jumping back and forth between the body and the subject field. One action, done!
Compatibility
Subject line auto-fill works seamlessly with:
- Gmail
- Outlook
- Yahoo Mail
Adding a Subject Line to a Snippet
Ready to set it up? Here's how:
- Head over to the Expand section in your MerciApp.
- Create a new snippet or open an existing one.
- In the Snippet Content section, click
Add a subject. - A Subject (optional) field appears — type in your subject (e.g., Project Follow-up).
- Fill in your Snippet Name and Snippet Trigger, then save.
Once you insert the snippet into a new email, your subject line fills in automatically. Magic! ✨
To remove the subject from a snippet, just click Delete subject.
Heads Up: Replying in a Thread
When you insert a snippet into a reply within an existing thread, the subject line won't auto-fill.
Why? Changing the subject mid-thread would actually break the conversation on the recipient's end — and nobody wants that! So auto-fill stays off in that context.
Need to change the subject anyway? Just type it in manually directly in your email client's subject field.
Running into any issues? Don't hesitate to reach out via chat — we're here to help!
Updated on: 22/05/2026
Thank you!