Converting stereo to mono

[Jane Ferguson]

I would like to use an audio interface but it ends up in two separate tracks. For example, if I sing, the vocal is just on one side in the headphones, or if I play guitar and sing, the vocal is all in the left and the guitar is all in the right. Is there any setting to convert the audio to dual mono so the same thing is heard in both ears?

[Vicalely Erickson]

I get the same thing.