i just reset my id and password will all the devices need to re sign in or will they be ok using old information?

i have several phones and devices on my account and i kept getting messages that were not being sent from my phone, but it looks like they were to another iphone in my account, so I changed my id and password now can i just use that id and pw my self or will i have to share the info with the other phones and devices on my account i really dont want to do this. i rather keep it to my self so unwanted messages cant be sent