Before you click on the Analytics icon, is it greyed out or is it purple?
If it's greyed out, that means your user doesn't have access to Analytics. You may need to navigate to the Adobe Admin Console to setup the proper permissions for your user. You can learn more about that in the documentation here.
It`s a problem, I log to a page via marketing.adobe.com , select Sign it with an ADOBE ID , when it`s open I have Adobe Experience Cloud panel , click upper right button to navigate Analitics and I see this massage
“See the big picture with customer intelligence from Adobe Analytics, the industry-leading solution for applying real-time analytics and detailed segmentation across every marketing channel.Link Account Learn More”
When you log in with sc.omniture.com, you are actually logging into the Analytics only authentication system. Since the Experience Cloud Admin Console is only accessable by users that are logged in via their Adobe/Enterprise/Federated IDs, the system is asking you to log into the Experience Cloud.
What you likely need to do is log in via marketing.adobe.com and navigate back to Analytics via the solution switcher in the upper right. Once you're back into Analytics using your Experience Cloud login, you should see the migration tool.
As a side note, your Analytics login might use the same username and password as your Experience Cloud login, but they are not the same system. Similar to how you could use the same username and password on two different websites.