Update einfracz-migration.md

docs.it4i/einfracz-migration.md

 # Migration of IT4I Accounts to e-INFRA CZ
 
-todo
+[e-INFRA CZ][1] is a unique research and development e-infrastructure in the Czech Republic,
+which provides capacities and resources for the transmission, storage and processing of scientific and research data.
+IT4Innovations has become a member of e-INFRA CZ on January 2022.
+
+The e-INFRA CZ membership has the following implications for IT4I users:
+
+## New IT4I Users
+
+* After the migration all new eligible users will create an account on e-INFRA CZ which will then be propagated to IT4I systems.
+* All new non eligible users will create an account following the standard procedure.
+
+## Existing IT4I Users
+
+Users with an existing account will have their account migrated to e-INFRA CZ automatically and ready to use
+after finishing the set up according the instructions in the email sent by CESNET.
+
+If you have any question regarding the migration or need help, contact the [support][2].
+
+[1]: https://www.e-infra.cz/en
+[2]: mailto:support@it4i.cz