Hi Eileen, and welcome to planDisney!
Now that you have purchased your theme park tickets, I can tell that a Walt Disney World Resort isn't far behind.
What you have described is something that I experienced when it came to my family's individual theme park tickets. Similar to my experience, I believe they will not have to link their tickets to their accounts because they are linked to yours. As long as each party member is included on your
Family & Friends list (and vice versa), each member of your family will be able to access their tickets in their
My Disney Experience app.
Another thing that you can do is share their
Disney MagicMobile passes with them, which digitally houses their theme park tickets and Disney Resort key (if you have a resort reservation). To do so, select the three lines at the bottom right and select "Tickets & Passes," and find the first ticket and "Add to Device," and it will find your passes and give you the option to share the passes.
If all else fails, feel free to call (407)939-4357, and a cast member will be able to assist you. I hope this helps.
Please let us know if you have additional questions.
Have a magical adventure!
Raquel