Follow the below-stated set of commands in order to merge the feature branch with the master, I am assuming that you are in a branch called featureBranch and you want to merge the changes of the featureBranch with the master,
First checkout to master branch(being present in the changes receiving branch)
git checkout master
Now pull the latest changes in master,
git pull origin master
Merge with the featureBranch
git merge testBranch
Push the changes to the master
git push origin master
That's it, you are done. I hope it helps you!