Square Uv map: fill the Uv layout This is my Uv map

My target is to max and optimize my Uv, in particular I would like it matches the whole Uv space. One solution could be scale the whole Uv from x axis and move all until the match will be perfect but, I should watch that corners and slides will match perfectly with the gray square in the background (it looks a &quot;more or less&quot; method).
I'm not sure this would be the best way to achieve the the best result.
My question is:
Is there a way to spread the UV all long the UV space, keeping its topology? Any advice? Or, is there a method to fill the gap of the uv space? Can a feature of Bledner achieve this?
EDIT
My Uv map was created with an unwrap
Thank you so much!
Hopefully your 2D cursor is at the bottom left of your UV layout image area - if not, position it there.

In toolbar area, choose "2D Cursor" as Rotation/Scaling Pivot.

In the UVs menu --> select "Constrain to Image Bounds"

Now select all of the vertices in your UV.

If the island is not flush with the bottom left: grab (G) and move so the edges are flush with the bottom left (the constraint will ensure that you cannot drag the island past the bounds)

Now, scale (S) - you should be able to scale to the image bounds.