Hi chrgilles

Each Phase has their own fields and the fields from earlier phase still there, but in the historical of card.

If you need to keep a field in all of your phases you must:

1. Create the same field into all phases
2. Using automation When the card entry in the phase you will update the next field with the content from earlier phase and going on

3. 

   Using a condition where the card is come from

4. 

   Suppose that you can go back phase, you must use the automation to update the content.

I hope that help you.

Good luck.

Okay wonderfull thanks so much, all is clear !