You can invite users to Zyte projects by going to the Members page:
If the person has a registered account already, they can be added via Add a Member button:
If the person doesn't have a registered account, they can be invited to join the project by clicking Send an Invitation and entering their e-mail address:
An invitation will be sent via email where they can click a link and complete the Zyte signup process. After they have signed up, they will become members of the project automatically.
Please note that project members have restricted permissions -- they will be able to deploy and run spiders, but not use Scrapy Cloud addons (Zyte Smart Proxy Manager (formerly Crawlera), Splash).