When you want to use someone else's content, and it is not covered by one of the copyright exemptions, then the solution is to get a license. This usually involves some negotiation, and payment.
Examples of when you would get a license:
The licenses that you will deal with are private contracts, not statutory licenses. Therefore, the terms and conditions are negotiated between you and the copyright holder. RocketLawyer.com has a copyright license template that shows the basics. Not all licenses look like that. In fact, there are verbal and implied licenses; it's just not wise to use them in our environment.
Remember that you can suggest and request terms when you contact the copyright owner!
Fortunately, almost all recent text works formally published in the United States are in the Copyright Clearance Center. Some of them have a form you can fill out and pay at the end to get a ready-made license. The rest have contact information for the copyright owner (aka rightsholder.)
The Harry Ransom Center's WATCH database is the best way to look up copyright owners/rightsholders working for authors. Make sure to check both the real name and the pseudonym.
With informally published or unpublished text works, you have to rely on detective work, web searches, and any contact information about the authors that is provided with the work. For example, check the About page of a web site, or ask the family in whose attic a journal was found.
With musical works, there two or three separate copyrights!
This is why you can have an opera by Mozart, whose lyrics and tune are solidly in the public domain, but almost all the recordings of performances of it are copyrighted!
Generally if you want to use a song in a video, you will need permission from the copyright owner of the recording. But if you wanted to use the tune and write your own (non-parody) lyrics to it, you would need permission from the copyright owner of the music. If you wanted to quote the entire lyrics at the heading of a chapter in your novel, you would need permission from the copyright owner of the lyrics.
If licensing for the content is available through the Copyright Clearance Center (which it usually is for United States text materials) then definitely use that!
Do a web search on the copyright owner, and if they have publicized contact information, always use that to contact them. Otherwise, certified mail is a respectable and reliable method of contacting the copyright owner with your request.
What should you say? Formulate your message using the guidance of this Permission Letter template.
Your copyright owner may say yes without any changes. They may say absolutely not. They may say yes but with some conditions and limitations. And they will set the amount that they want to be paid, and how they want to be paid.
You are allowed and expected to say yes or no or make changes right back, based on your own interests. Hopefully you will come to a mutually satisfactory arrangement in only one or two rounds of negotiation.
Once you have agreed to the terms, you and the copyright owner both need to sign. Generally this happens by the copyright owner signing the license and sending it to you. You sign it, keep one copy, and send another back to them.
How you will pay your royalties is something you will have arranged with the copyright owner.
Your license probably came with specific terms about what material is to be used and how, who can access it and how, etc. Be sure to do as you promised, or else the contract is voided. Generally that means you could be vulnerable to being sued for damages or even statutory damages. So make sure that if you said you were only using it in Course X, it's not to be found in an email attachment or in Course Y; and if you only got permission for a clip, you're not using a larger piece.
At the end of the license term, you will need to consider whether to renew it. You will need to initiate the renewal. You or the copyright owner might renegotiate any of the terms at this time.
An Orphan Work is a piece of content that's still under copyright, but it's copyright owner either
Usually this happens when the creator of the work died and the work was either never formally published, or was but is out of print now. If whoever inherited the copyright doesn't expect to get much profit from it, they may not consider it worth their time to respond to requests.
Unfortunately, U.S. law says that if the copyright owner can't be reached, you still can't use the content.