It can be compared with a product-oriented syllabus, which focuses on completed acts of communication, the outputs.
Example
A process-writing syllabus would focus on the processes writers use to complete their tasks, such as collecting information, organising ideas, drafting and revising, rather than just the features of the products of writing, such as letters, compositions, notes, reports etc.
In the classroom
Working on the writing processes is hard work for learners because it involves thinking, organising and planning, but it is time well-invested in skills that will enable the learner to become an autonomous writer. One way to apply a process approach to tasks is to provide the language they need on demand as they work, rather than before they start. This can be done by the teacher, by referring the learners to useful language lists or dictionaries, or by other learners.
See also:
https://www.teachingenglish.org.uk/article/product-oriented-syllabus
Further links:
https://www.teachingenglish.org.uk/article/syllabus-writing
https://www.teachingenglish.org.uk/article/which-syllabus-traditional-holistic-syllabus
https://www.teachingenglish.org.uk/blogs/dario-banegas/teaching-english-through-controversial-topics