Your System Preferences on your iMac—your Apple ID and Family Sharing settings are at the top.
Payment & Shipping: Manage the payment methods associated with your Apple ID, and your shipping address for purchases from the Apple Store.
iCloud: Select the checkbox next to any iCloud feature to turn it on. When you turn on an iCloud feature, your content is stored in iCloud and not locally on your Mac, so you can access it on any device with iCloud turned on.
Media & Purchases: Manage the accounts linked to Apple Music, Apple Podcasts, Apple TV, and Apple Books; select purchasing settings; and manage your subscriptions.
See all your devices. At the bottom of the Apple ID sidebar, see all the devices linked to your Apple ID. You can verify that Find My [device] is turned on for each one (see Access your iCloud content on your Mac.