The short answer
Yes, for US customers where the tax applies. HighLevel's sales and use tax FAQ says it began collecting sales tax on applicable subscription sales on August 1, 2022, and on usage billed through the wallet on January 1, 2023. The Terms of Service say all fees are exclusive of taxes, so the prices on the pricing page do not include them.
What HighLevel says about tax
The Terms of Service state that fees exclude sales, VAT, GST and use taxes, and that you are responsible for taxes tied to your use of the platform. For wallet spending, HighLevel calculates the tax after the end of each calendar month and collects it from the wallet balance at that point, so expect a tax deduction from the wallet early in the month. Taxes are listed as non-refundable. The FAQ covers US customers only and notes that rules vary by state, but the page itself does not list which states are taxed.
If your business is exempt
Resellers and exempt organizations can send HighLevel an exemption certificate. The FAQ asks for the Multistate Tax Commission's Uniform Sales and Use Tax Exemption/Resale Certificate or another certificate your state accepts, with HighLevel, Inc entered as the seller, and sent with supporting documents to Salestax@gohighlevel.com. Send it before your next invoice, since tax already charged may not come back when the Terms call taxes non-refundable. Whether your agency qualifies as a reseller is a question for a tax professional.
Charging tax to your own clients
Tax on your HighLevel bill is separate from tax you charge your own customers. HighLevel includes tax settings in the CRM that let a business add, manage and apply its own tax rates to products, services and invoices it sends from the platform. Whether your services are taxable depends on your state and what you sell, so confirm the rates and rules with an accountant before you turn tax on for client invoices or order forms.
More answers in HighLevel questions. For costs, see GoHighLevel pricing or run the cost calculator.