How to change the highlighted image size?

Hi,

I downloaded the free version of Adelle theme, and I have the following doubt: the featured image is 300 x 200 pixels on the page that lists the posts, see: [https://prnt.sc/eicbg3]. However, I’d like to set the image at 640 pixels wide and variable height, example: [https://prnt.sc/eicguc]. Is it possible to do this, if so, how I do this?

Thanks in advance!