Can my regular doctor do the endoscopy in his clinic?

Depends. Some states like new york, require special certification to do enodscopies in offices and clinics. Otherwise, endoscopies are performed in the hospital.
Depends on the doc. Most people have their endoscopies performed by gastroenterologists who are specially trained to perform these procedures. If it is a simple endoscopy and you are relatively healthy, these can be done in the clinic. More difficult cases are done in the hospital.