You can share a document by selecting the option Public and change the option to Can View. Alternatively, you can select Anyone with the Link and share the document URL. In both settings, you can share only with view permission. To edit a shared document, they need to create an account in Creately.
If you're a non-Creately user wanting edit access, you will be prompted to create a new account. You can follow the steps which will appear in the screen when you proceed ahead to sign up. Once you complete the simple process, you will be able to login and start editing. But, be mindful that a free user can only edit with upto 60 shapes per document.
If you wish to edit with unlimited amounts of shapes and create unlimited documents, you will need to upgrade your account with a subscription plan.