OLDER IPHONE OR IPAD, OR AN ANDROID PHONE OR TABLET
If you're trying to connect your audio output device to an older iPhone or iPad, or an android phone or tablet with an 1/8" (3.5mm) combo jack for connecting a pair of headphones, and/or a microphone, you'll need a break out connector LIKE THIS ONE to convert the single combo headphone/microphone jack into 2 separate jacks. One jack for your microphone and a separate jack for your headphones.

NEWER IPHONE OR IPAD WITH A LIGHTNING CONNECTOR
You'll need a lightning connector to 1/8" (3.5mm) TRRS Jack adapter LIKE THIS ONE so that you can use the breakout connector above. (Sorry, I couldn't find a 1 adapter solution.)