How to merge a branch to main branch in Github.

In Terminal or Command Prompt: 

git checkout main [switch to main branch]

git pull origin main [grab latest updates from main branch]

git merge master merge [master branch to your main branch]

git push origin main [push your changes to main]

How to delete all commit history in GitHub & repush to main?

Create a new Branch:

git checkout --orphan latest_branch

Add your all the files:

git add .

Save the changes with commit:

git commit -m "commit message"

Delete Main Branch:

git branch -D main

Rename latest_branch to main:

git branch -m main

Force update the repo:

git push -f origin main

Git Configuration and Commit Command

Git Configuration :

git config --global user.email "you@example.com"

git config --global user.name "Your Name"

Commit comman for Mac:

git reset --mixed origin/main 

git add * 

git commit -m "This is a new commit for what I originally planned to be amended" 

git push origin main

Commit comman for Windows:

git add * or git add --all
git commit -m"first message"
git remote add origin "LINK"
git push -u origin master