@moein sakhavat - Any paid or Education plan can – as you know – use the Visitors feature to make the board public and share a link to anyone  on the Internet.

can I add member, so that it is not Always necessary to share a link. Without additional costs

If you have the Business or Enterprise Plan, you can add registered Miro users to a board using the Guests feature – only paid license users can be added to a Team or Project.

Here’s another help center article that further explains the differences between Visitors, Guests, and members → https://help.miro.com/hc/en-us/articles/7045408248594-Visitors-guests-and-members