Passwords

I have a very old ipad 4 which I haven’t been able to update

for over two years. I don’t hold anything on importance on it, than photos, so

the fact that It won’t sync over to my new ipad eighth generation is not a

problem to me. What I want to know is - can I use my original Apple ID on the

new one and my old password, and if I do would it make my old ipad obsolete and

unusable?  I would rather like to keep

the other one going as well as the new one. I am holding back setting it up

until I can find out the answer to these questions.