my old email address and I can't remember the password.
If you still know that old email address ⤵️
See -> If you can't connect or sign in to iCloud
If you can't connect or sign in to iCloud - Apple Support
Check your Apple ID via your email box, see this Apple article: If you forgot your Apple ID
If you forgot your Apple ID email address or phone number - Apple Support
OR see -> Having trouble signing in?
https://iforgot.apple.com/password/verify/appleid
Have you forgotten your password? -> See this Apple article: If you forgot your Apple ID password
If you forgot your Apple ID password - Apple Support
Then see this Apple article: What to do after you change your Apple ID or password
What to do after you change your Apple ID or password - Apple Support
FYI -> Your Apple ID is the personal account you use with all Apple products and services. It includes the email address and password you use to sign in, as well as the contact, payment, and security details that you use with Apple.
You can’t merge multiple Apple ID accounts.
Get more help:
Call Apple in your region see: Contact Apple for support and service
Contact Apple for support and service - Apple Support
Or -> Contact Apple Support -> Get Support (apple.com)