The Internal Revenue Service allows you to deduct most mileage you drive for business purposes. However, the miles you drive to and from your place of work are considered commuting miles and aren't usually deductible.
Anytime you are driving from your home to your first job of the day or your regular place of business, you do not get to deduct or count those miles because they are commuting mile.
Any other miles that you drive for your business are your miles driven for the business. You are supposed to keep a driving log in case the IRS asks for it. If you don't have that, you can pull together your jobs through invoices or some other way.
Here is a link with more information on driving in your business.
https://turbotax.intuit.com/tax-tips/small-business-taxes/business-use-of-vehicles/L6hi0zzzh
This mileage rule does not apply to OTR truck drivers.