I need to enter a 10% wear and tear to my tax form

Hello there, LJT.

Tracking depreciation in QuickBooks Self-Employed is currently unsupported. However, you can enter this in your TurboTax or tax pro account you're using in filing your taxes at the end of the year. You can use this link for more details about tracking depreciation from TurboTax.

For your guide in preparing your transactions for tax filing, you can use our How to use QuickBooks Self-Employed reports to fill in your tax return article. 

Let me know if you have other questions. Take care and have a great day!