TL;DR of the post, generated automatically.

OP wants every edge of a plane to be transparent in Blender, and has only got one side working so far.

• The ask: Make each edge of a plane transparent, not just one side.
• Progress so far: OP has managed to make one side look that way.
• Clarification: OP attaches a 600 by 600 image of the effect they want, since the title alone doesn't say it all.