Hello @Teodora Parvova (Alorica Inc) ,
Azure AD enables the use of Azure AD features for guest users who are invited into the Azure AD tenant to collaborate . If you have Azure AD Basic for EDU A1 free licenses , you can invite as many guest users as you need for collaborate. As mentioned in the licensing guide for B2B
Guest users can use free Azure AD features with no additional licensing requirements. Guest users have access to free Azure AD features even if you don’t have any paid Azure AD licenses.
Generally the B2B guest invitation follows the 1:5 LocalUser:Guest ratio of 1:5 for Azure AD paid licenses. However since Azure AD Basic for EDU is a free license with all the Azure AD free capabilities and more you can invite as many guests as you like and those guest users will only be able to use the Azure AD features available to your users with the Azure AD Basic for EDU A1. In case you require the guest to use a feature which is part of azure AD premium then you would need to have one AAD premium license for being able to invite 5 guest users to remain compliant.
Hope the clarification helps. If the details in the post help answer your query , please do accept this post as answer so that its helpful to others in the community as well. In case you have any further queries ,feel free to let us know and we will be happy to help .
Thank you .