If you itemize deductions--and many people will not be able to do that for 2018 because the standard deduction is so much higher--then sales tax is one of the itemized deductions.  BUT you cannot just isolate the sales tax you paid for the wedding, nor can you call it a "major purchase"  (like a car)  on your tax return.  You can choose to enter the total of ALL your 2018 sales tax receipts (some people really do save them all) OR you can let the software calculate your sales tax deduction based on your income and the tax rate in your area.

SALES TAX

You can enter the sales tax you paid in 2018 by going to Federal>Deductions and Credits>Estimates and Other Taxes Paid> Sales Tax.  

Sales tax is an itemized deduction.  If your state has a state income tax, you have to choose between using the deduction for your state tax paid OR the sales tax deduction, whichever is higher.  The TT process will suggest one or the other as you prepare your return.

“Major purchases” that you can enter for the sales tax deduction include:

Motor Vehicles (cars, trucks, motor homes, RV’s, sport utility vehicles and off-road vehicles

Aircraft or boats

Mobile homes

Manufactured housing

Building materials for major home improvements

You cannot deduct: furniture, jewelry, home electronics such as TV’s or computers

https://ttlc.intuit.com/questions/1901222-which-deduction-should-i-choose-sales-tax-or-income-tax

https://ttlc.intuit.com/questions/2566624-how-much-sales-tax-did-i-pay-last-year

https://ttlc.intuit.com/questions/3148443-how-do-you-define-major-purchase-or-major-item-for-the-sal...

https://ttlc.intuit.com/questions/1900791-how-do-i-find-my-local-sales-tax