Make Current User Name Default on the Employee Field of the Time Tracking Form

The following are the available options:
 

A. Customize and set employee restriction to a role
1. Navigate to Setup > Users/Roles > Manage Roles

2. Click Customize or Edit Role
2. On the Employee Restriction field, select own, subordinate, and unassigned "or" own and subordinates only
3. Click Save

Result: Employee field drop down list will automatically default on the current user name and user can still have an option to select other employee depending on the restriction.
 

B. Customize and Restrict Time and Expenses to a role
1. Navigate to Setup > Users/Roles > Manage Roles

2. Click Customize or Edit Role
3. Mark Restrict Time and Expenses
4. Click Save

Result: Employee field is automatically displayed the current user name using the Role and is no longer editable.
 

C. Use Employee Center role

Result: Employee field is automatically displayed the current user name using the Role and is no longer editable.