Here's how to add rounded corners to your videos in Premiere Pro.
Step 1:
Reduce your clip's scale to about 80% in Effect Controls to create working space.
Step 2:
Go to Effects panel and search for "Roughen Edges". Drag it onto your clip.
Step 3:
In Effect Controls, adjust these settings:
Change Edge Type to "Cut"
Increase Border to around 200
Set Fractal Influence to 0
Step 4:
Adjust the Border value to control corner roundness: higher numbers for more rounding, lower for subtle curves.
Your video now has stylish rounded corners.