Hi I had to change my apple ID for my work phone. I created the new apple ID< how to up update my phone? It wont let me add the new ID

Here's how you change the email address you use for your Apple ID:

1. Go to https://appleid.apple.com and sign in.

2. In the Sign-In and Security section, choose Apple ID.

3. Enter the email address that you want to use as your Apple ID.

4. Choose Change Apple ID.

5. If you changed your Apple ID to a third-party email address, check your email for a verification code, then enter the code. Learn what to do if you didn't get the email. --> If you didn't receive your verification or reset email - Apple Support

6. If you use services like iCloud or Messages to share with friends and colleagues, sign in to those services with your updated Apple ID. --> What to do after you change your Apple ID or password - Apple Support

For more details, read the document: "Change your Apple ID" --> Change your Apple ID - Apple Support

Incidentally, you do NOT create a new Apple Account/ID. You change the email address used as the ID on the old account. If you have already used this to create a new account, you will have to create a new email address to use with the old one if you now wish to change it. It is best to stay with your old account since that has all your purchases tied permanently to it.