Sometimes you want to share the plants and care schedule in your account with someone else-for example a family member or a friend that will help out with watering while you're on vacation.
With the premium version, you now have the option to invite family and plant sitters to your account. As family, they have access to all your plants and sites and also the ability to add, remove, and change settings for your plants. As a plant sitter, you have the ability to mark tasks as completed, but not to change, remove, or add plants to the account.
It is also possible to share an account by logging in with the same credentials on another device. Note that if you have signed up using Apple login, this option will not work.
Read this article on how to change Apple login to an email login