In my assignments the students can see the view all submission button.
I can out find out why. Any suggestions please.
Users with capability 'mod/assign:grade' or 'mod/assign:viewgrades' can see the button.
If students can see it, then that means that have one of those capabilities assigned to one of the roles they have at the assignment level or above.
Use the 'check permissions' link on the assignment page (either in the settings block or in the settings drop-down), select one of the students on the course and Moodle will tell you what roles they have and what capabilities that gives them.
You can then fix the role definition at the site level (or, possibly, fix an override at the course / activity level).