To get seller protection, it is absolutely necessary to add tracking details, so why there is no easy way of doing this for all transactions is beyond me.
Here's what I mean, after logging into PayPal, your "Recent Activity" shows...well your recent transactions, and you can click each one to see its details page. The URL for the details page looks something like https://www.paypal.com/myaccount/transactions/details/1234567890ABCDEFG, where 1234567890ABCDEFG is the PayPal assigned transaction ID.
The transaction details page does allow you to add tracking information quite easily...
The problem is reaching this page once your transaction is no longer showing up in the "Recent Transactions" list.
If you go to your "Activity" tab, you can see all of your transactions and expand them to see their details, but that list does not have a way of adding tracking information. Further, there is no link to the separate transaction details page from any of the transactions here. There is, however, the transaction ID shown (but for some crazy reason not linked to the details page...why PayPal, why?)...
So in order to reach the transaction details page, you need to copy the transaction ID and then manually create a URL to it, in the same form as I showed earlier...
This is just simply bad UX design on PayPal's side. It's locking out the user from crucial functionality for a no good reason and I'm sure it's a contributing factor to many claims against the seller gone wrong. Maybe someone from PayPal will read this and will do something about it...but then the "new" user interface has really been in shambles for a while so I am not holding my breath.
-i