Tax is set per rate and applied per service, and whether prices include it is a decision that's hard to reverse. Settle it before the first invoice.

Rates and where they apply

Tax in ClinyPal is set per item, not per clinic. Open Settings, then Taxes, and add each rate with a Name and a Rate as a percentage, such as GST at 10. A new clinic starts with four, GST 10%, VAT 20%, HST 13% and Sales Tax 0%; keep the one you charge and archive the others. Then, on each billable service (under Pricing) and each product, choose the Tax that applies or N/A for none, so a catalog can mix taxed treatments and tax-free items. Expenses pick a rate the same way so the tax paid is worked out for you.

Check whether prices include tax before the first invoice. Switching between tax-inclusive and tax-exclusive rewrites every taxable price in the catalog, and once the first invoice is issued it can't be switched at all.

Archive a rate you no longer use. Lines already invoiced keep it; a new invoice can't use an archived rate and says so.

The Taxes settings page listing tax rates with their names, percentages and last update, and on the hovered row view, edit and archive buttons, beside a New Tax button.
The Taxes list with Sales Tax and the other rates a new clinic starts with.

This list is one for the whole clinic; every location uses it, and there's nothing to set up again when you add a location.

Added on top, or included

Whether a service priced at $85.00 means $85.00 plus tax or $85.00 with tax inside is the clinic-wide Tax calculation method in Invoice Settings. The service's price field is labeled accordingly, tax inclusive or tax exclusive. Switching the method reprices the whole catalog so patients pay the same, and the method locks once invoices exist. The Tax summary report totals tax charged either way.