The only way I know of to set up the Offline grading option as a default has to be done by the system admin. You will need to talk to your system admin and have them do it at:
Site Admin Settings>Plugins>Activity Modules>Assignment>Offline grading worksheet check the box to enable
After that is done all new assignments will have the offline grading worksheet box checked. Now this may not be something they want to do as default for an entire site.
What I suggest to my instructors for assignments and quizzes that they have specific settings that they want to have on each succeeding one is that they make a "template" with all their settings but not the specifics of the directions/questions/ etc. Then hide it. So if they make a template for Weekly assignments that are worth 25 points, needs offline grading, etc. all the settings are there without them having to remember them all and all they have to do is duplicate it, change the title, fill in the directions, check show in the settings and move it to the topic box they want it in.