You may register for LSAT administration using any of the following mediums-
Online Registration- Choose LSAC Online Services for LSAT Online registration. For registering, Click Here.
Telephone Registration - CalltoLSAC for LSAT registration on Phone No.- 215.968.1001 between 8:30 AM and 7:00 PM ET, September-March, and between 8:30 AM and 4:45 PM ET, April-August.
Note: LSAC's busiest day is Monday, so you can avoid delays if you call later in the week.
Mail in Registration - You can register with LSAC by sending completed registration form to-
Law School Admission Council 662 Penn Street Box 2000 Newtown, PA 18940-0998, USA