Yes, you must get a visa to get to Bhutan. Visa is the most very necessary document to travel to any county. You can obtain the visa with the help of an approved tour operator. For obtaining the visa, you should apply in advance. You must provide the necessary documentation to the travel operator. You cannot enter Bhutan unless you get visa approval.
For safety, we suggest you keep a photocopy of passport visa pages and flight tickets and keep them separately from the originals. While applying make sure that your passport must be valid for size months after the date you leave Bhutan. Above the Himalayan, the team member will help you during your visa application.