Yes, if are self-employed, or you are getting paid through a 1099-NEC, or 1099-MISC, you can write off the business portion of your phone.
You can also write off the mileage on the vehicle. If your business is a sole proprietorship, you can enter that mileage in the self-employment income and expenses section of turbotax, under wages and income for your personal 1040. Schedule C is where a sole proprietorship's business revenue and expenses are reported on a 1040.
If you are claiming actual vehicle expenses on a S corp or partnership return and the vehicle is not in the business' name, you should maintain an accountable plan for your business records.