Create the tax types your business uses, assign them to offerings and review which invoices a rate change will affect.
Steps
Open Settings > Business Setup > Tax Setup.
Add or edit the tax type and enter the applicable tax/service-charge fields.
Check the display labels and any effective-date/version choices.
If asked whether existing invoices should be updated, review that choice carefully before confirming.
Assign the correct tax type to packages/add-ons and check a sample invoice calculation.
Current invoices versus future defaults
Changing a tax definition can have a different effect from changing a tax choice on one invoice. Use the current confirmation to decide the scope. Review existing signed/paid documents and your accounting requirements before recalculating them.
Tax-exempt clients
Use the client's tax-exempt settings and tax ID field where applicable, then check the specific invoice calculation. Do not assume every older invoice has been recalculated merely because the contact was changed.
Get the rate from the right source
Releventful applies the rates and rules you configure. Confirm your tax obligations with your tax adviser. TaxJar, VAT and service-charge settings are separate options that need their own setup and verification.
Related guidance
Keep existing invoices on their old rate
The tax-change confirmation asks whether existing invoices should use the changed rate. Choosing to keep the old rate creates a replacement tax definition for future catalog use while retaining the previous definition for existing references. Review the specific invoice and its calculated taxes; changing a client's exemption setting is not an immediate bulk rewrite of every stored invoice.