how to give animation solidworks part for to show in grapcad screen?

Its just too easy.

Whenever you uploading the model in Grab-cad library or workbench , there should a place in which the page asking for "URL to video"

Simply provide the URL to video and your animation will be live at Grab-cad model review section (Means in your model page).

Answered with a tutorial: https://grabcad.com/tutorials/how-to-give-animation-solidworks-part-for-to-show-in-grapcad-screen

If you have any problem to create the account and uploading the animation in You-tube than message me, I will clear your doubts.!!

you need to create an animated .GIF file (not too large) and upload it as a render then set it as your default image.

Check this tutorial: How to save your animations as GIFs in SolidWorks