Redimensionnement rapide

I guess I'm not understanding the OP given the other replies, but ctrlA ctrlG s* enter 25 enter (PC version)

* the S key.

If you want a precise 1000x2500mm to 250x625mm add a 1000x2500mm bounding box to your art.

Or if your artboard is 1000x2500mm, export to pdf, place, scale (embed if you want to edit)...

There is the Artboard Resize With Objects script: https://github.com/alexander-ladygin/illustrator-scripts

But when you only need this for pixel export, then you can scale when exporting.

Sofia,

There is no single (whether quick or no) way to downscale a document/file that covers all the possible different requirements depending of purpose.

Just to mention a single aspect that can be crucial in some cases, the required resulting resolution of raster effects and raster images depends on the possibly different intended viewing distances of the original and the downscaled document; in some cases, minimized file size is required.

Do you need this just for exporting a raster image?