How do I find out my iPhone 5s passcode

You can not find out your pass code if you have forgotten it but you can attempt to recover your iphone at the link below. You will lose your data.

If you've forgotten the passcode on your iPhone, or your iPhone is disabled – Apple Support

If you did not set up the passcode yourself or the phone is linked to another Apple ID, you have pretty much no chance without getting in touch with the original owner.

Activation Lock for iPhone, iPad and iPod touch – Apple Support

you will not be able to 'find out' your passcode. you will have to follow this

If you forgot the passcode on your iPhone, or your iPhone is disabled - Apple Support