The list of countries whose citizens do not require a visa (if staying up to 90 days) can be found here.
Holders of the Schengen Visa can travel to one or all member countries (22 EU states and 4 non-EU members) depending on the type of the visa. The Schengen Visa allows the holder to travel within the Schengen countries for a maximum of up to 90 days in a 6-month period. Further information can be found here.
Letter of invitation
Participants requiring a letter of invitation in order to attend the conference are asked to email email@example.com. Please note that this procedure aims to assist those who need to obtain a visa or an entry-permit to attend the conference. A letter of invitation is not an official invitation covering fees and other expenses and does not imply any financial support.