Hi, The suggestion for this pattern is 14-count white fabric. If you tap on the TITLE underneath the picture, it will take you to a screen that gives you a description of the pattern i.e. Size AND the suggestions as to what fabric to use that is located halfway down the page.
Of course, you could use any fabric you want.., 14-count fabric and stitching "over one" would be the same size as using a 28-count evenweave fabric and stitching "over two".

I'm not an employee of ECS, but one of the stitchers who saw your question on this "chat." :)

Thanks for all the informations

Your welcome and welcome to the "chat"! 😀