In QuickBooks, you can categorize this type of transaction under Schedule C: Other business expenses. Also, I'd suggest consulting with an accountant so you'll be assisted properly in claiming your self-employed related deductions.
For the moment, what you can do though is choose the closest category available for your transactions. To add a deduction, here's what you'll need to do:
On your QBSE account, click Transactions in the left menu.