The question can be answered very easily: Where everyone who consumes your project sees it.
Some common examples...
YouTube and Vimeo credits can be placed in the video description or in the video itself.
On your profile page, add a "Music" section to place the credits. We have created a special page with even more information about streaming here: https://filmmusic.io/faq/67
Most commonly, credits are placed on a "Credits" screen found in the settings menu.
Credits should be placed in the program for the production. If no program exists, a voice announcement can be made.
Credits should be placed in the credits portion of the film, either before or after the main film section.
Credits should be voiced - usually at the end of the production.
It is more common to purchase an extended license, but credits may be shown visually in the production, or done as a voice-over in audio-only media.
It is more common to purchase an extended license, but it is possible to record a voice-over for each piece of music used.
It is more common to purchase an extended license, but credits may be posted in a public area of the retail space.