1. Sign in to your Shopify account.
Log in to your Shopify account by entering your login details.
2. Go to Settings.
In the main control panel, at the bottom left, click Settings.
3. Select "Users and permissions".
On the Settings page, find and click Users and permissions.
4. Generate a code or copy an existing one.
If you want to create a new code - click: Generate new code. Copy and send it to the person you will be working with. He will need to use this code when sending a cooperation request. 
5. Copy the original Shopify store link.
Also copy and send the link (your-shopname.myshopify.com) which you can find in: Settings - domains (see image) .
6 . Review and confirm the request
When a person makes a request using the code, you will need to review and approve the request in the same block to grant them access. You will also be able to determine what permissions you will grant to the store.
7. Access without code.*
In the Collaborators section, select the option "Anyone can send a collaborator request". But this method is not so safe. Anyone will be able to send you requests. Of course, you will need to review and approve to grant access.
People who want to administer your site will be able to send requests without code. You will need to review and approve each request to grant access. The prompt will appear in the same place as in step 5.
8. Everything. Invitation confirmation.
The person you invited will have to accept the invitation by email. email and login to Shopify.