There are a few things that are good to know before you travel to Myanmar. Some things that may seem fine in the US are frowned upon or illegal there, so it's good to know what's what.
Although taking pictures of landmarks, buildings, and temples is totally fine, you must always ask permission before taking pictures of people. It is considered especially disrespectful to take pictures of meditating monks.
Religion
Most Burmese are devout Buddhists, and expect you to respect their faith. One thing to do in Burma is NEVER, EVER, EVER DISRESPECT THE BUDDHA OR DO ANYTHING THAT COULD BE PERCEIVED AS DISRESPECTING THE BUDDHA. You can be arrested for “Hurting religious feelings,” which is punishable with up to 4 years in prison. It is also frowned upon (But not illegal) to disturb those who are meditating or praying in a church. During religious ceremonies, wear appropriate clothes, in fact, you should always try to wear traditional Burmese garb, the Pasu for men and the Longyi for women.
Body Language
In Burmese have strong feelings about the head and feet because of their Buddhist faith. The head is considered holy, while the feet are considered filthy. So you should avoid touching people’s heads while in Myanmar, as this is considered disrespectful. You should also avoid using your feet for anything other than walking. Do not point to or touch anything with them, and keep them folded under you while sitting on the ground or floor. Especially avoid pointing your feet at a person or a Pagoda (Buddhist temple).
Spending
When buying things in Myanmar (likely a souvenir) avoid things made out of ivory or animal skin. These things are illegal, and the government is fighting against the ivory trade. Buy from authorized antique shops, and remember that religious trinkets or souvenirs cannot be taken out of the country.
Source:
https://www.tripsavvy.com/dos-and-donts-in-myanmar-1629596