if the same subject on email google will same it automatically convert it into a thread.
In this case, We can update the subject for each email using the submitted id. For Example.
Here are the steps how can you add id on your subject
1) Go to your Form on App
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2) Edit your form which you want to update using Edit Form button
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3) Go to the Details tab
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4) Just add {id} after your subject line like “Your Subject Line {id}”
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5) Hit the save button now you will get the subject like “Your Subject Line 123”, “Your Subject Line 124”, “Your Subject Line 125”, etc…