There are some places wherein it is required for men to become circumcised. There are also some places wherein circumcision is not considered to be something that people have to do. When you say circumcised, this means that the extra skin that can be found in the penis will be cut.
Some men would get circumcised at birth. Yet the recommended age for boys to become circumcised is around 10 and above. For uncircumcised, the foreskin will not be cut.
To get circumcised or not will depend on the personal preference of a person but some people are saying that it is more hygienic to have the penis circumcised.