Seasonality is an attribute of delivery locations.

Create seasonality
Click on , then enter the seasonality label.
Click on to save the creation.
Modify a seasonality
In the "Seasonality" menu, simply click on the seasonality to modify. It is then possible to modify the label.
Click on to save the changes.
Remove seasonality
In the "Seasonality" menu, simply click on the seasonality to remove, then click , before confirming the deletion.