We all use energy everyday from everday actions like turnng on lights, driving, washing clothes, etc. Most of the energy we useally use is dervied from the burning of fossil fuels which produce greenhouse gas emissions(GHGs) like carbon dioxide which are released into the atmosphere. We need GHGs in our atmosphere to survive as they trap heat and absorb energy, but too much of them can lead to devestating impacts on our health, economy and the environment.
A carbon footprint is the total amount of GHG emissions produced directly or indirectly by an individual, household, organization, etc and the size of it depends on many factors like home size and types of vehicles used. You can calculate your carbon footprint and see what actions you can take to reduce it by using a carbon footprint calculator like this one: https://coolclimate.org/calculator