My wife and I are college professors. Each year attend one or two conferences for scholarly activity. What and how much is deductible? Where do I file it?

Those expenses are deductible as job-related expenses.  Please go to Personal>Deductions & Credits>Employment Expenses.

I suggest reviewing the rules and limitations on travel expenses before you proceed.  https://www.irs.gov/taxtopics/tc511.html

Also keep in mind that job-related expenses are miscellaneous itemized deductions, you can deduct those expenses only to the extent that they exceed 2% of your adjusted gross income.

What if my employer provided a portion of expenses?

Then you can only deduct the expenses you paid without reimbursement.