The example you link to uses the property “skew” of transform. Skew isn’t proposed in Webflow UI.
You can google “css skew” to get custom code and add it in Webflow as code. That’s the easisest way.
Now there must be some ways to play with divs in webflow to make something that look like a parallelogram in the end (by creating elements as masks and rotate them) or to use images as background to do the same (like two tiangles with a square angle, one on each side)…