
Explanation/Reference:
Note:
* Make the account in the SharePoint domain.
* Step 1: Create accounts that are required for a SharePoint Search service application To register a managed account On the Central Administration home page, in the Quick Launch, click Security.

On the Security page, in the General Security section, click Configure managed accounts.

On the Managed Accounts page, click Register Managed Account.

On the Register Managed Account page, in the Account Registration section, type the user name and

password that you want to use as credentials for the service account.
If you want SharePoint Server 2013 to manage password changes for this account, select the Enable

automatic password change check box and configure the parameters for automatic password change.
Click OK.

Step 2: Configure the SharePoint Search service
Reference:https://technet.microsoft.com/en-us/library/gg502597.aspx