European perspective here: It varies, but I still write one for 80-90% of applications. - 10% of online applications explicitly only have one form field to upl

European perspective here: It varies, but I still write one for 80-90% of applications. - 10% of online applications explicitly only have one form field to upload CV - 20% of them have separate fields which most often are "CV, last employer's reference, cover letter, others" - the remainder just let you upload as many documents as you want with the expectation that at least the 3 mentioned in the last bullet are included.