Hey, howdy, hey, Kendall,
Welcome to planDisney. It's a pleasure to help a fellow Guest make the most of your adventure at the Disneyland Resort, The Happiest Place on Earth!
I'm guessing you may be familiar with the Family & Friends Lists available through Disney World's My Disney Experience. At Disney World, Guests with a MyDisney account create profiles for each person in their party and have the ability to link those profiles to theme park tickets and reservations for dining and activities.
At the Disneyland Resort, your My Disney account doesn't include a Family & Friends List feature. Without the per-Guest profiles of a Family & Friends List, theme park tickets, dining reservations, and reservations for tours and other activities are linked to your My Disney account and not associated with any Guest in particular until they are activated or used. In that way, your reservations work more like what you might experience at something like a regular restaurant in your community. So, like when you make plans to go out with a group of friends, you may simply share the details of the reservation with other members of your party which they can then put in their personal calendars. I sometimes copy-paste details from the Disneyland site or make a screenshot of a reservation screen in the Disneyland mobile app to send to others in a text message or email.
Most Disneyland Resort plans in your My Disney account can't be shared with the My Disney account of another Guest. However, theme park tickets are somewhat unique. The My Disney account used to purchase or perform the initial link of Disneyland Resort park tickets is the primary owner of those tickets. Those tickets may also be linked to as many other My Disney accounts as needed. Any account with the tickets linked to it may be used to view, modify, and cancel theme park reservations. Likewise, any account with your tickets linked to it may be used for activating and using the park tickets at the theme park entrances. Another great feature of this system is that any account with your linked tickets may also be used for redeeming Lightning Lane return times.
Tony's Tip: One of my favorite features of the flexible approach to linking plans in My Disney accounts at the Disneyland Resort is that a MagicBand+ can be associated with any Disneyland Resort park ticket linked to your account, regardless of who the Guest is. So if you happen to have any MagicBands+ from a previous visit to the Walt Disney World Resort, you may link those bands to your My Disney account in the Disneyland app and then associate your bands with whichever tickets you'd like. You can even switch it up from day to day in case you'd like to accessorize to match your outfit each day.
Have a magical time, Kendall!
~Tony