Do I receive a roll number before or after completing the LPU admission process?

You are not given a roll number beforehand at LPU. Your roll number is assigned after you complete the admission process. Roll numbers are typically used for administrative purposes like class attendance and exams. Since you wouldn't be enrolled in classes until after admission is finalized, assigning a roll number before then wouldn't make sense. This process is done after all the students have completed their admission process.