If you are not yet on LOTW, here is a helpful link on how to setup and use it: g4ifb.com/LoTW_New_User_Guide.pdf
For Confirmations, QSL cards do NOT require a SASE (Self Addressed Self Stamped Envelope). I enjoy getting them and I am more then happy to provide and pay myself for return postage if you are kind enough to take the time to send me one. Although, if you send a SASE or GS, it is always appreciated but not necessary. I log ALL QSOs not just HF. This is including those via Satellite, VHF/UHF and unless it is a net, even repeater contacts.
In addition to physical cards, I also QSL via LOTW (My preference), eQSL (AG) or via the ARRL Bureau (ARRL 6th District) but it might take some time. These get shipped about twice a year. I also Upload to QRZ , HRDLog and ClubLog when I get a chance or about once a month.