@Heghine Lalayan - Your options will vary by plan type. Here are your options when considering “edit” capabilities, and without making them full paid license team members:
Free Plan - You would have to make your clients a full team member.
Team, Consultant, Business, Enterprise*, and Education - You would use the Visitors feature, aka, public access/”Anyone with the link”. It is also worth noting that clients can access your boards this way without having a Miro account of their own.
Consultant, Business plans and Enterprise - You have access to the Guests feature, where you can give direct access to a board to non-team members, and you can specify different access levels--view, comment, edit--on a per user basis. Note: A Miro account is required by guests, but a Free Plan is all they need.
*Enterprise Plan users may need to contact their Miro Company Admin to enable Visitors feature for them if they do not see the “Anyone with the link” option - more on this here.