Add a white border to many images

Paint Bucket only works on stills, not video. Besides, it's an obsolete effect.

If you want it to work on video you need to add a mask from Alpha Adjust, invert and invert Alpha.

One way is to...

Make a rectangular in the EGP.

uncheck Fill and set Stroke as desired.

Save as a Source Graphic.

Drop that over your imaged.

In order to make a unique copy, Alt drag from the timeline or duplicate in the Project Panel.

Do not use copy/paste (if you change one, all will change shape).

You can use the Roughen Edges effect with the correct settings to achieve a border of any color with rounded corners.  It is, however, a bit resource intensive.

I'm not at my editing computer, so I don't have those settings now, but can post them if there is interest.

You can also create a frame in Photoshop.

You need to create and store a graphic file. Highly recommend using the png format, as that works best between Premiere and other apps.

So you create the white graphic. Store it where you can 'grab' it again, like in a CC local Library perhaps.

So you have a clip on V1. Put the graphic on V2, and on that layer, a mask to block out the middle of that graphic. Done.

You can copy/paste that 'clip' to anywhere else in the sequence of course. With the mask active.

There's other ways I'm sure will get posted.

Oh ... in the Essential Graphics, make a white box the size of your sequence, make a mask in the middle of that also in the graphic, store the graphic. That will 'hold' the open area in the middle clear.