Your cell phone cost is not related to the standard mileage rate and can be claimed to the extent that the phone was used for your business.
The standard mileage rate is meant to include the cost of fuel, maintenance, repairs, insurance, and depreciation.
Expenses not included in the items covered by the standard mileage rate may be deducted as a business expense. This would include parking fees, tolls, and garage rental when incurred for business purposes.
The following TurboTax articles will explain more:
Standard Mileage vs. Actual Expenses: Getting the Biggest Tax Deduction
Tax Tips for Uber Driver-Partners: Understanding Your Taxes
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