The iPhone 11, iPhone 11 Pro and iPhone 11 Max don't have headphone jacks. This will be an annoyance for any audiophile that's invested in a decent set of cabled cans or avid music fan that's not interested in the good, not great, Apple Airpod true wireless earbuds.
How do I plug my headphones into my iPhone 11?
https://www.youtube.com/watch?v=UDvewXb_gLg
What headphone adapter do I need for iPhone 11?
Apple Lightning to 3.5 mm Headphone Jack Adapter.
Can iPhone 11 use wired headphones?
Yes because if the headphone jack you are using is 3.5mm then it will work because the iPhone 11 is updated past IOS 10 which is the requirement for the IOS device you choose to use for the product.
Why won't my wired headphones connect to my iPhone 11?
Check for debris in the headphone port on your iPhone, iPad or iPod touch. Check your headphone cable, connector, remote, and earbuds for damage, like wear or breakage. Firmly plug your headphones back in. If your iOS device has a case, remove the case to get a firm connection.