Chaplain, home office, mileage computation

[BCiocco]

I am a corporate chaplain. I have a home office from which I answer emails, make calls, file reports, study,and have couples in for premarital counseling. I also store materials that I pass out and have a library that I make available to employees I serve. 
I work for a company and am contacted out to serve several companies. My company's main office is in another state and I do not have office space there. I do not have, nor am I offered, office space at any of the companies I serve. I make regular, weekly and bi-weekly rounds at the companies I serve, attend and preform weddings and funerals. 
There is discussion as to when mileage should start. Some are saying mileage starts at the first location; others say it starts from the home office. Which is it? This is important because some locations are 35 miles away. 

[Texas Roger]

Are you a W-2 employee or do you receive a 1099-MISC for self employment?

[BCiocco]

I am a w-2 employee of the company that provides the service.

[Texas Roger]

W-2 employees are no longer allowed to claim a mileage deduction as of tax year 2018. 

[BCiocco]

Thanks.
Actually, we claim the mileage to the company and are reimbursed. That part of our salary becomes non-taxable as a mileage reimbursement. 
The question still is, when should the mileage start according to IRS rules.

[Texas Roger]

It would depend on what your company says you can claim.  If you were self employed, your home would need to meet the tests to be a principal place of business for you to deduct mileage from your home to your other places of business. You can see the tests for determining whether it is a principal place of business in IRS Pub. 587 starting on p. 3: https://www.irs.gov/pub/irs-pdf/p587.pdf