using my Apple ID I added my child as a family member on my phone. I see he can send emails using his iCloud.com email address but he wants to send messages in a group chat on the iPad. I can’t figure out how to add the account to iMessage
iPad, iPadOS 15
If he uses your iPad, it will send messages from you. It's best that he uses his own Apple ID (Create an Apple ID for your child - Apple Support). Regardless, messages can only be sent from him if he is logged into a device using his own Apple ID.
See also:
What to do before you sell, give away, or trade in your iPhone or iPad - Apple Support
https://www.apple.com/families/
The child needs to be logged into their iCloud account on their device to send messages. Messages cannot be sent from iCloud.com
Outside of Educational and Enterprise establishments, iPad and iPhone are principally intended to be a single-user device - and are not intended to shared in the same manner as you may be accustomed when using a Windows PC or Mac computer - which has multiple user profiles/accounts.
For managed environments, where multi-user usage is possible, the Deployment Guide provides appropriate guidance.
Shared iPad overview – Apple Support
Be aware that for unmanaged environments, be aware that if you sign-out of iCloud and other Apple services - and allow another user to sign-in - you’ll not be able to change back for 90-days. So as to prevent account abuse, some critical Apple services will only allow one change of signed-in AppleID (on a device) in a 90-day period. as such, unless you fully understand and accept the implications, you would be well advised to reconsider any attempt to share your iPad with another user.
You might be best advised to consider purchase of dedicated iPad for your child - and set this up for a minor with appropriate restrictions as you determine.
You may find this information to be helpful with setting-up an AppleID for a minor - and considering appropriate controls:
Apple for Kids - Official Apple Support
Help your child set up an iPhone, iPad, or iPod touch - Apple Support
Family Sharing and Apple ID for your child – Apple Support
Use parental controls on your child's iPhone, iPad and iPod touch – Apple Support
he is using my iPad, not his own device. since he is 10, I couldn’t creat his own Apple ID, is is just linked to mine. Is it possible to have him use my iPad using iMessage?
How does my child send messages using iCloud.com account
