How can I find out what my passcode is? I’ve never had to use until now.

If your passcode.

See the Apple Support article(s) below for IOS 15.2 or later..

Passcode - How to reset your iPhone, iPad, or iPod touch when you forgot your passcode (IOS 15.2 or later).  *

ASC YouTube for how to restore your iPhone if you forgot your passcode - Apple Support.  -

See the Apple Support article(s) below for earlier than IOS 15.2 . 

Passcode - If you forgot the passcode for your iPhone or your device is disabled.    *

See the Apple Support article(s) below for earlier than IOS 15.2 . 

Passcode - If you forgot the passcode for your iPad or your device is disabled.     *

Do you mean your Apple ID password right? Not your iPhone passcode!

if you still remember what is your Apple ID password see this article to learn how to change it ☞ Change your Apple ID password - Apple Support

but if you forgot it See this article ☞ If you forgot your Apple ID password - Apple Support

Try the following:

▷ Forgotten iPhone Login Passcode.

Need more help?

• Call Apple Support at 1-800-APLCARE.
• International Support.
• Contact Apple Support.
• Chat using Messages.