There is a global search bar you can use to find an applicant in your system. If this search bar is turned on it will show in the top right hand corner of the Administration Dashboard.
NOTE: Only Global Admins can turn this on. From the Home page of the Administration Dashboard > Click the "Administration" section. > then Click the "Site Settings" icon.
Under the General Settings header there is radio button labeled "Enable Global Search for Applicants". Toggle this to yes or no depending if you would like this feature on or off.