Yes, CBSE has officially released the sample paper for class 10 and 12th board exam on its official website for the year 2018 - 2019. For your convenience and to provide you with an exam similar situation around you they provide it earlier. Marking scheme and the solution to each and every question is there.
You don't have to move here and there in search of sample papers. You can download sample paper of each subject with solutions and marking scheme from
CBSE Class 10 Sample Papers 2019
CBSE Class 12 Sample Papers 2019