To changed register manage account password in SharePoint, if it has change in the active directory

Cause: I have changed my farm credentials (password) in morning and just try to create web application.

The password supplied with the username Domain\username was not correct. Verify that it was entered correctly and try again.

I tried to create new web application using my farm credentials but no luck and it has given below error

There are two ways to change farm user Password

• Using stsadm –

        This updates password forcefully without any validation

• For SharePoint 2010
• Go to command prompt and navigate to bin location of 14 hives
• C:\Program Files\Common Files\Microsoft Shared\Web Server Extensions\14\BIN
• stsadm -o updatefarmcredentials -userlogin <domainusername> -password <newpassword>
• It will give you message as “Operation completed successfully.”  
•  Now reset IIS.
• For SharePoint 2013
• Go to SharePoint 2013 Management Shall
• stsadm -o updatefarmcredentials -userlogin <domainusername> -password <newpassword>
• It will give you message as “Operation completed successfully.”   
• Now reset IIS.

It’s worked for me.

• Using SharePoint Central Admin
• Browse to your SharePoint Central Administration.
• Navigate to Security from Quick launch.
• Click on Configure Managed accounts under General settings as shown below.

• Click on Register Managed Account to add the Service account which you would Change to.

• Fill in the service account information in the Register managed Account.

• If Password is not set base on password policy then gives error.
• Now it’s time to change the Service account for the Web Application.
• Navigate back to Security from Quick launch shown below and click on Configure Service accounts

• In the Service Account page, select the Web Application for which you would need to change
• Select the appropriate service account and hit OK.

• Now Reset IIS.

Reference and for more details: http://technet.microsoft.com/en-us/library/cc263417(office.12).aspx