Yes I have another apple iCloud and need to merge it with the one I have on this new phone

Need to gain access to a old iCloud I forgot 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

See -> If you can't connect or sign in to iCloud

If you can't connect or sign in to iCloud - Apple Support

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.

I have another apple iCloud and need to merge

You can’t merge multiple Apple ID accounts.