There are many writing classes available online through reknowned universities. You can also find many talks and presentations online about writing topics. Many institutions charge a fee for access but some courses are available for free. Here are some noteworthy providers of online writing education and instruction.

Catapult
Catapult offers online writing workshops, bootcamps and classes that run for 4 to 8 weeks.

Creative Writing Courses at Stanford
Stanford offers creative writing courses online that are taught by instructors from Stanford’s writing community.

CreativeLive
CreativeLive offers dozens of writing classes from experts on writing books, essay writing, business writing and more.

edX
edX offers free writing courses from Harvard, Barkeley and other universities on a variety of writing topics.

Gotham Writers
The Gotham Writers Workshop offers online classes in a number of subjects including, fiction, nonfiction, scriptwriting and more.

MasterClass
MasterClass provides courses on a variety of subjects from experts in their fields. Some of the writing instructors have included James Patterson, R.L. Stine, Judy Blume and Margaret Atwood.

MIT OpenCourseWare
This MIT site contains course materials and more from multiple writing-related MIT courses.

Ted Talks
Ted Talks has a growing number of talks about the subject of writing. They also have talks from successful authors.

Udemy
Udemy provides thousands of courses online on many subjects. These include a large number of writing-related courses.

Writer's Digest
Writer's Digest provides online writing workshops through its Writer's Digest University website.