California Sales Tax for Interior Designers - Labor Charges
You may also charge your clients for labor associated with a taxable sale.
For purposes of calculating sales tax, labor charges are
generally divided into three basic categories: fabrication, repair, and
installation.
In general, tax applies to charges for fabrication labor,
but not to charges for labor considered repair or installation.
Nontaxable labor charges should be itemized separately on
your invoice.
Source: California Department of Tax & Fee Administration (CDTFA)
Course: https://salestaxsolutions2000.com/california-sales-tax-interior-designers