Below are the scopes of a Feature. A Feature can be deployed at below mentioned levels

• Farm Level:
  • The feature at this level can affect the entire farm.
  • The feature can be activated at farm level from Central Administration >> System Settings >> Manage Farm Features
    

• Web Application Level:
  • The feature at this level can affect single Web Application only.
  • The feature can be activated at web application level from Central Administration >> Application Management >> Manage Web Applications >> Select a Web Application >> Click on Manage Features from Ribbon
    
    
• Site Collection Level:
  • The feature at this level can affect entire site collection.
  • The feature can be activated at site collection level from Site Settings >> Site Collection Administration >> Site Collection Features
    
    
• Site Level:
  • The feature at this level can affect only a single site.
  • The feature can be activated at site level from Site Settings >> Site Actions >> Manage Site Features