@Julia Aydin - Google Translate may be leading to some confusing on my part, so I will first clarify that Boards and Projects are two separate things in Miro:

Only team members/paid seat holders can see/create/interact with Projects.

But, if you are asking, “With the Starter Plan subscription, can I give edit access to boards to people who are not paid members of my team?”, the answer is yes, you can.

To further explain how you would do this, there is something else that requires clarification: Guests and Visitors are two separate roles in Miro. The Starter Plan does not support Guests, meaning you cannot give a non-team member direct edit access to a board. Instead, non-team members can only access boards using the Visitors, i.e.,  Anyone with the link access.

You can read more about the difference between visitors, guest, and members here.