How to delete cookies for some site?

First you need to open site in your browser and click on settings icon near site name (arrow 1 on the image). Then click "Cookies and site data" (arrow 2 on the image)

Open 'Cookies and site data' dialog

Then press "Manage on-device site data":

Press 'Manage on-device site data'

And then press delete icon near all 5 entries:

Delete all cookie entries