Hello aspirant
Digilocker is a digital document locker launched by goverment of india so that one can access important document's any time any where.
Yes your migrations certificate from digilocker is valid and acceptable for any admissions as it is digitally verified and signed by cbse.
In some cases authority may accept your migration certificate( digital) but may ask for a physical one also but they will not reject you on basis of this.

Hope this will help you

You can get more information about diet from here

Thank you