Hello sir 🙏🏻        Small hole in your teeth means cavity has started . so what you will do is , visit your dentist and get your check up done . In case if you dont have any pain or on taking x ray also if we dont see any deep cavity then it can be filled by removing the infection present over there . In case if your cavity is deep or if you  have pain then it goes for root canal treatment . But dont leave it like that ,  because if you leave it then due to food lodgement the cavity might become bigger so please visit your dentist as soon as possible and save your healthy teeth 😊🙏🏻 stay healthy.        Thank you .

Small hole may be due to caries.consult a dentist get xray of tooth.if tooth is decayed, get it filled.also get your teeth cleaned to remove stains on teeth.

There is pit and fissure in teeth which may lead to caries and possess a risk in management of oral health and hygiene. The xray of the affected tooth need to be done to make a proper diagnosis May require conservative treatment

The picture isn't clear .

From the information and pictures provided, you seem to have caries which need to be taken care. And can plan the treatment after the investigation is done such as x-ray.