You have two ways of reordering the field instructions for each mailbox:
Reordering fields on the Fields page
In your mailbox, navigate to the Fields page
Click-and-drag on a field to move it up or down:
Reordering fields on the Export page
This option is helpful if you wish to have a specific output order of your columns separate from the default order dictated by the process above.
In your mailbox, navigate to the Export page
Click on the + New Download button
Click-and-drag on a field name to move it up or down:
I created fields, and now I want to create the table. Can I drag the fields into a table?
It is not possible to drag already created fields into a table. To have fields inside a table, you need to create a new field of the Table type and then add the desired fields as columns of that table. Afterwards, it is recommended to delete the individual fields to avoid confusion when extracting data.