Where do I enter my expenses for travel related to volunteer work?

 If you are itemizing your return you will enter these miles by clicking in TurboTax Online

• Federal
• Deductions and Credits
• See All Tax Breaks
• Show More Next to Charitable Donations
• Start next to Donations to Charity in 2018
• Add next to Mileage and Travel Expenses
• Enter your miles and travel expenses including lodging and meal expenses

To enter your charitable miles driven click the following in Turbo Tax Desktop:

• Federal
• Deductions and Credits
• I'll Choose what I work on
• Start next to Donations to Charity in 2018
• Yes under "Do you want to enter your donations for 2018"
• Add next to Mileage and Travel Expenses after entering the charity name
• Enter your miles and travel expenses including lodging and meal expenses

Understood about TurboTax, but it looks like the OP tagged this as ItsDeductible, so for travel expenses, those would go here: https://itsdeductibleonline.intuit.com/secured/Mileage.htm

Of course, if you like TurboTax and you use a version of TurboTax which supports import from ItsDeductible, you can then import your deductions into TurboTax that way

Okay, but what if it's not miles driven, but some other sort of travel expense, like taxi or train fare?

You can enter those as travel expenses rather than mileage.

1. federal>deductions and credits>donations to charity 2019>donations
2. Here you will record the name of the charity. Then add travel expenses, which is at the bottom of the screen 
3. then there will be a screen that says "Enter your mileage and travel expenses for XXX"
4. At the bottom of the screen will say other travel costs.  Here you put in the cost and the description of other travel.