@Fasil Abdu Thanks for reaching out.
If you assign a M365 license to external user, they have all the features like a normal user in your tenant. There is no difference.
Here is how you can assign a license to the guest user : https://learn.microsoft.com/en-us/microsoft-365/admin/manage/assign-licenses-to-users?view=o365-worldwide#assign-a-license-to-a-guest-user
Hope it helps.