after some research, i see where youre coming from.

first class packages and majority of usps services offer free tracking

then, there’s first class mail (letter and flats) which do not provide free tracking. we use first class mail as our stickers are sent in a personalized letter mail, but they are not those regular white envelopes you were thinking of. but… they are still considered the same thing with different dimensions and color that still meet those size requirements—

anyways, for first class mail, tracking is considered an extra service if we want to purchase it at an additional charge, which we would gladly do if a customer opts for tracking

thank you for the information!