Confused About Addressing Formally or Informally Your Colleagues On The First Day Of The Job?

The beautiful answer to this question depends on various factors like country of origin, the culture you are brought up in, whom you follow, which country you live in now. 

Perhaps it sometimes appears as you are asking the other person to provide their status or position in the world concerning you. This position may involve age, job, education, religion, and even marital status. 

Since English is a language rather than a culture, it depends on person-to-person choices.  

Well, I believe If you are addressing someone from armed services, a Doctor, a Judge or, a supreme delegation of the nation, you should be addressing them with properly designated salutation.

In business situations, you can use formal titles like, 

                   Sir (adult male of any age)

                   Ma'am (adult female of any age)

While addressing casual or a very close relationship, you can use an informal form of address:

• First name (friends, students, children)
• Miss/Mr + first name 

However, there will always be some people and some professions that require more formality than others.

If you still are hesitant about it, consider taking an opinion from the addressee. 

This isn't tough at all. Always remember to strike the conversation with your pleasant smile and extended handshake. Everything will fall in place.