Looking for a board? Bottom edge inside front door.

[Bowman]

I can't quite find what I'm looking for.

I've covered up a cat flap; the outside of the front door is okay, but the inside still has the "hole."
Therefore, I would like to find a good board, something similar to what is used on the backs of wardrobes or equivalent. (white)
But I can't find this in regular hardware stores? Or not on the web at least (byggmax etc.)
I would also like to find some type of screw that would look nice with this.

Can anyone give me some tips?

 

[Mats]

it was white-painted mssonite that.
I think that for example Bauhaus or a regular building market has it.
Byggmax's assortment is somewhat limited.

 

[Bowman]

Yes, okay, thank you for the response!
I will check this!