From December 2016, Singapore passport holders can visit Myanmar for 30 days without visa. This exemption is not applied for foreigners who live or work in Singapore. The mutual signed by Singapore and Myanmar government also allows Burmese tourists to visit Singapore without visa.

A similar agreement amongst Asian countries including Vietnam, Laos, Brunei, Philippines, Thailand, Cambodia and Myanmar indicates that the citizens of these countries can travel to Myanmar for 14 days for purpurse of tourism without visa. 
The restriction of the agreement shows that free visa is only for those who arrive by Yangon, Mandalay or Naypyidaw international airport. Border crossing, specially who travel by their own vehicle needs to apply Myanmar Visa before arrival.
For business visa or long travel over 14 days, a valid visa is needed. 
In any case, you will need a passport with 6 month validity and blank pages so that he immigration department can stamp on. 

Accordingly, travelers from America, Europe, Africa and other countries in Asia need to obtain Myanmar Visa. With the endless effort from Myanmar government, you can now apply online for visa pre-arranged on arrival through many border checkpoints.