How to create connected system for Active Directory?

AFAIK the active directory does not provide a HTTP base API Appian could connect to. But what is your use case?

I have the requirement to create integration with AD to give uses functionality to provide uname and pwd to approve rows in interface.

Why is that necessary? A user is already logged in into Appian using SSO or username/password. Appian does not support such an additional authentication OOTB.

We need to implement 21 CFR part 11 signatures while approving any records.

OK, but for electronic signatures to work, your user does not need to enter his credentials a second time. At least as far as I know.

Maybe you can give us a bit more insights into what you want to achieve.

Yes, the user wants to click on approve button in interface for that record item and it should be approved through SSO without entering uname and pwd. 

OK. That is the standard of what we do in Appian. You assign a task "Approve something" to a person and that person clicks the approve button and the process continues.

Ok, but when user is approving the item, it should approve via SSO. How to connect appian with AD for such approvals.

The user has to login (SSO) to be able to open the task and click the button. Is this not good enough?

No that is not good enough. I know a bunch of Pharma companies use Appian. We are tasked to ALWAYS PROMPT for user name and password when an approval process is being executed. This is the standard called 21 CFR Part 11. Been around for years. Right now, we cannot use SSO for our appian application until we figure out how to connect to ACTIVE DIRECTORY to verify what the user enters for user name and password during the approval cycle is correct. We are currently doing this verification using local accounts.

Isn't there some other pharma company that has implemented 21 CRF Part 11 approvals using SSO?