Permanent and total disability, is that in reference to disability through social security or the veterans affairs disability?

Not sure where you are seeing that or why you are asking.   You do not enter income received from Veteran's disability on a tax return. 

 If you receive Social Security disability you need to enter your SSA1099 on your tax return if you also have other income.

Go to Federal> Wages & Income>>Retirement Plans and Social Security  (SSA1099 and 1099RRB) to enter your SSA1099.

As for a "disabled credit"----

There is an extra amount added to your standard deduction if you are legally blind.   Your federal return does not provide any other credits or deductions for saying you are disabled, with one possible exception.  

There is a credit for the Elderly and Disabled which is so small that very few people benefit from it—-it has not been updated/increased by Congress for decades.

ELDERLY OR DISABLED CREDIT https://www.irs.gov/help/ita/do-i-qualify-for-the-credit-for-the-elderly-or-disabled

There are some states that provide various credits to elderly/disabled folks, so watch for that when you prepare your state return.   The states that I know of that have anything for elderly/disabled are AZ, CT, DE, IA, MO, ND, NY, VE.   There may be others.

The IRS has a precise definition for Permanent and Total Disability for the Credit for the Elderly or the Disabled in this IRS document:

What Is Permanent and Total Disability?

A person is permanently and totally disabled if both 1 and 2 below apply.

1. He or she can't engage in any substantial gainful activity because of a physical or mental condition.

2. A qualified physician determines that the condition has lasted or can be expected to last continuously for at least a year or can be expected to result in death.