BUSINESS MILEAGE FOR SOLE-PROPRIETOR

Seems like it, you may want to pull up Pub 463 for the rules about business mileage.

Yes of course.  You will need the beginning miles ending miles and business miles - those are the miles

he drives visiting clients and can deduct from his office or home.  You also should include for no benefit his commuting miles that he drives to and from his office so you will wind up with total miles which include business miles which are deductible, personal miles (non-deductible and commuting miles (non-deductible).  You also need the make and model of the vehicle (e.g. 2018 Ford F150).  The first year you have a choice of using actual expenses (oil changes, repairs, car insurance, gasoline) or standard miles.  If you use the standard mileage rate you must stick to it for the life of the car and if you use actual expenses (you get a percentage of the costs  e.g. if business miles are 15% you get 15% of the costs).

Sorry, disregard my part about the office as I reread it as she not he is working from home.

@wethepeople   She works out of her home and drives to and from the clients to perform her services.

There is nothing here that indicates she does any work at home, or does any work at home other than at the kitchen counters when she isn't baking cookies. 

It's almost as if the question is phrased to get an answer that assumes facts not stated.