If you are prompted to sign into your Apple ID, simply input your username and password into the pop up. The device will verify your login information and then activate iMessages if successful. If you don’t have an Apple ID, see this guide for detailed instructions on creating one. iMessages may take up to 24 hours to activate because Apple needs to verify that the phone number and Apple ID match. Activation usually happens within an hour. [1] X Research source
In the You can be reached by iMessage at: section, you can add, remove, and select email addresses to receive iMessages. On an iPhone, you can also add or remove the phone’s number to or from this list. Other devices will only display this phone number in the list once it has been enabled from the iPhone. [2] X Research source In the Start new conversations from: section, you can select one address others will see when you send an iMessage to them. On an iPhone, you can also add or remove the phone’s number to or from this list. Other devices will only display this phone number in is list once it has been enabled from the iPhone. [3] X Research source
If you haven’t used Messages before on this mac, you will be prompted to enter or create your Apple ID. Input your Apple username and password, or click on Create Apple ID to create a new account.
If you are already logged into your Apple account, you will not see this login option.
