Smooth and Finish the Corner

What happens here

After applying the mud with the roller, immediately use a corner finishing tool (also known as a corner knife or corner trowel) to smooth out the applied joint compound. Run the corner tool along the entire length of the corner, pressing firmly to embed any drywall tape (if used, though not explicitly shown in this rapid demonstration) and to create a clean, sharp, and smooth corner line. This action removes any excess mud and ensures a professional-looking finish. Repeat the pass if necessary for a perfectly smooth surface.

Goal: Create a clean, smooth, and sharp drywall corner