Forwarding is NOT recommended as each invitation sent to a guest has a unique guest ID.
When a guest forwards the invitation they received to other people, they will be able to access the invitation as the guest that it was intended for, and any comments or replies made by additional guests will be under the name of the original guest who had forwarded the invitation. This will cause the same person to show up as RSVPing over again each time.
If the host forwards the invitation to other people, it will ask them to sign in since it is a unique host ID for the host of the event.
You will want to either add guests directly by email or text, or you can purchase the shareable link to share with your guests.