Where do I enter the $50/month credit I am eligible for, for having a foreign exchange student living with me last year?

[GeoffreyG]

The $50 per month for hosting a foreign exchange student that you refer to is actually a tax "deduction," and not a tax "credit."  (The difference here being that a credit is a dollar-for-dollar reduction in your actual income tax liability, whereas a deduction simply reduces the amount of your income subject to being taxed -- thus making a tax credit the much more valuable of the two.)

But, that aside, a detailed answer to your question is provided at the following clickable AnswerXchange link:

https://ttlc.intuit.com/questions/3674572-foreign-exchange-student-deduction

There you will find a significantly more detailed discussion of this particular deduction, as well as instructions on how to enter this information into TurboTax.

Thank you for asking about this.