Keychain can be synced with your iPhone, iPad and MacBook providing it is enabled in iCloud. To enable it on your iPad, open Settings, click on your Name, select iCloud and then click on Keychain and turn the iCloud Keychain toggle button on. To enable it on your MacBook, open System Preferences, click on iCloud and then tick the box next to Keychain. It may take some time for your Keychain to sync on both devices. You will also need to make sure that you are logged into the same Apple ID on both devices.