How to auto populate from admin(Staff) user input?

How to auto populate from admin(Staff) user input?

I have created a form for students. The corresponding staff (Class teacher or adviser) need to fill student details. I haven't set any mandatory fields(except email). The staff can fill more details if available. When submitting the form the mail will send to respective students with form link. Students can update their information. I have given permission to access the student form to the student. when student login to student form the data given by staff is already pre-filled. How can I do that?