git error: src refspec main does not match any. code example

Example 1: error: src refspec master does not match any. git

# You are trying to add an empty repository, add something first, like a readme
touch README.md
git add README.md
git commit -m "Initial commit"
git push --set-upstream origin master

Example 2: error: src refspec master does not match any error: failed to push some refs to android studio

git commit -m "initial commit"
git push origin master

Example 3: error: src refspec master does not match any.

git init
git add . //to add everything
git commit -m ''
git remote -v
git push heroku master