It has always been possible to assign different activities such as Discussions, Quizzes and Assignments to different students (in different Sections, previously created).
It is now also possible for teachers to assign content, such as an entire module (or individual module items) to existing sections, or to specific students. This functionality also applies to Pages.

Tip: As a tutor, you may think about supporting students in their learning by assigning different content and/or activities to different cohorts. Create Sections for your student cohort(s), and then consider assigning different content (in Modules or Pages) to them, alongside corresponding interactive activities (e.g. Discussions, Quizzes or Assignments).

To assign a particular Module to a section or individual students, use the three dots menu alongside the module and select Assign to ...

To assign a particular part of a Module (module item) to a section or individual students, use the three dots menu alongside the item and select Assign to ...

To assign a particular Page to a section or individual students, use the three dots menu alongside the page (in Pages) and select Assign to ...

Then follow the options to assign the content either to one or more Sections in the course, or to one of more individual students in the course.

Further details as to how to assign different content to different students is provided in the Canvas documentation:

Assign a Module to sections or individual students
Assign a Module item to sections or individual students

Notes:

This functionality works only for view access in the Student role. It doesn't seem to work for Observers. Further, you can't give Teacher-/TA-based roles viewing/editing access to specific Modules or Pages only, since they can always view/edit everything.
Be aware that if you add students to a Section before assigning the content, they would be able to access all the content until you've finished assigning Modules/Pages to particular sections. Therefore, you may wish to create the sections, assign the Modules or Pages to particular sections, and then allocate the students to the relevant sections.