@Carina Kenny - The Free Plan is limited to 3 editable boards, but unlimited users/team members as stated in the Plans and Features Available help article:

While you can create an unlimited number of boards in Free Plan, the following wording in the Free Plan help article will explain why you are seeing VEW-ONLY:

I only created ONE board and did it in the online version and when I added the fourth member, it turned out to be VIEW ONLY for everyone. Then I downloaded the MIRO APP and I see that some other employees of AWS have done boards so there are 3 boards there (I cannot see mine). So the 3 limit board it is not PER PERSON but PER COMPANY.  Is that correct?

@Carina Kenny - You are correct. A Free Plan team only allows 3 editable boards for the whole team and not for each team member.