Hi @Rebecca_England1, welcome to our Forum!
In an Organization membership is determined by the company email domain. For example, if an Organization is tied to the email domain @onetwothree.com, users with email addresses @onetwothree.com tied to their Asana accounts will be considered full Organization Members. Users registered in Asana with different email domains will be considered Organization Guests when invited to this Organization. Guests have limited access and can only see what is explicitly shared with them.
Therefore, if these clients invite you to their Organizations in Asana and your Asana account is associated with your corporate domain, you will be considered a Guest in their Organizations. It is not possible to turn a Guest into a Member or vice-versa.
If they want you to be a full Member of their Organizations, their IT Team would have to provide you with email addresses “@theirdomain.com”, and you would need to add these email addresses to your Asana account.
It is possible to have multiple email addresses associated with your single Asana account, and you can switch between the spaces you belong to: Managing your account settings | Product guide • Asana Product Guide
I hope this information helps!