For your requirement :
Consider Add Azure Active Directory B2B collaboration users in the Azure portal
In this a user who is assigned any of the limited administrator directory roles, can use the Azure portal to invite B2B collaboration users. You can invite guest users to the directory, to a group, or to an application.After you add a guest user to the directory, you can either send the guest user a direct link to a shared app, or the guest user can click the redemption URL in the invitation email.
Also consider Add Google as an identity provider for B2B guest users
By setting up federation with Google, you can allow invited users to sign in to your shared apps and resources with their own Google accounts, without having to create Microsoft Accounts (MSAs) or Azure AD accounts.