>buying things online
TLDR, don't.
Long answer.
If you are going to try buying things on the internet you need several steps taken before even begining. First you need to transfer a currency into a anonymous/not associated with you digital currency such as prepaid bank cards or gift cards. You can do this buy paying someone to buy it for you in cash that has changed hands several times as to not track the paper component, or by doing that and going to a store without cameras. Idealy the card should not be able to be tracked back to where you purchased it, such as going to another nation/state instead of the gas station 1 mile down. Now after you have obtained the card and not had it associated with you irl you can get anonymous to purchase something. You need a burner phone/computer purchased with cash exchanged several times and bought anonmously/no cameras on person or vehicle to/from location. Then use that computer which you will block the cameras on from a public wifi spot to purchase said thing. When traveling to a public wifi hotspot don't be seen by cameras/people who could identify you from purchase. Same thing applies as for the purchase of the digital currency.
After the purchase if it is a digital purchase you are done. If it is a physical purchase you have several options for anonymously picking it up. If in USA you can send it to a post office under someone elses name who will pick it up for you, just put the adress down like this
>*name of person picking it up*, general delivery, *post office adress 123456*
Then said person needs an ID card to pick it up but it can be done wherever you wish. You could do it yourself but then the mailman sees your ID to pick it up unless you make a fake ID and put down a fake name.
If using fedex via EU then same thing as above applies with general delivery. If using something else then pay someone to send it to their home or pay for a box at the mail office to send it to with cash and either have it in someone elses name to pick it up or do it yourself.
Congrats, you just bought something anonymously and privately online! Security of your purchase is a nightmare, at best. Just stick to purchases made with cleaned/exchanged hands several times cash done in person at non camera recorded locations you privately travel to and from.