Most of the foreigners need visa (children traveling on their parents' passports need visa too) and a valid passport to enter Myanmar.
There is a 14 days visa exemption for the people coming from the countries as follow:
Passport holders from the most of the countries are eligible to apply E-visa:
For more info, please see: http://evisa.moip.gov.mm/
A tourist visa can also be applied directly through a travel/visa agency in your home country or directly at the Myanmar embassy. A tourist visa officially costs between US$20 but runs up to €50 in some Western Europe countries.