Do you mean Codecs?
First determine which Codecs are supported by your online player and then use a video editing program (such as Adobe Premiere or something cheaper) make a new project, import the video, then export the video using the proper codec settings.
It would seem the most common file format used for online videos today is .mp4 which systems that don't do Flash (cell/mobile phones) can play perfectly fine.... But with each file format there is usually 3+ types of codecs to choose from, not to mention compression / quality settings for both audio and video.
If you do not have the proper codecs available on your system for encoding, there are a few web sites that have free downloads for them.
If you mean "Codes" then I don't know wtf yet talking about. :-p
Sites like YouTube generally can access, upload and convert pretty much any type of video file and all you need to do is select the file, maybe write a brief description and then click the upload button..... Then wait a few hours for it to upload.
If you're trying to upload a personal porn video to an online porn site, they should generally operate the same way as YouTube. Just upload and walk away while it processes and converts..... Maybe watch some porn while you wait, whatever floats your dingy.