I prefer to display To and From fields in all my Outlook mail folders. Can I make these fields appear by default in all folders?

When you create a new mail folder, Outlook automatically applies the Messages view. Therefore, to modify the default view, you must change the built-in Messages view. Switch to any mail folder, then choose View, Current View, Define Views. Select the Messages view, then click Modify. Click Fields, then drag the To field from the left side of the Show Fields dialog box to the right side, placing it where you want it to appear. Click OK, click OK again, then click Apply View to make the modified Messages view active on the current folder. Now, any new mail folders that you create will have this enhanced Messages view.

The second part of the solution is to clone the updated Messages view and apply it to existing folders. Open the folder you used to update the Messages view, then choose View, Current View, Define Views. Select the Messages view, then choose Copy. Give the new view a name (e.g., Messages To-From) and make it active on all mail and post folders. When the View Summary dialog box appears, click Fields to confirm that the To field is there, then click OK. Click Close to exit the Define Views dialog box. You now have a Messages To-From view that you can apply to any mail folder, new or old.