in out country Tanzania they charge us alots money if the track numbers didn't start and ended up with letters, so can you please help us save the cost and add letters beginning and ending of the track number of all orders please!?

Hello, I'm a particular and I usually like to send letters and small things, never more that 2kg to my different friends all over the world, I have been using the normal tracked letters and packages of the post office but it has already happened more than once that they write something wrong or they suddenly tell me it's way more expensive than it should for the weight and size, is there a way I can personally register the letters/small packages as a particular online and idk print a label? Or is there any other type of shipping for small parcels that I can use to send things to my friends?

I tried tracking my waybill number at the USPS online tracker, the waybill in not correct. they said it should began with two letters followed by nine numbers and ends with two letters. mine has an extra letter in the beginning QBS829202669CD.