You can download Sourcetree
You need to create a Personal Access Token in Github which will be used to for authentication purposes
Once you download Git for Windows, and complete the installation, the git bash window appears.
Navigate to the folder where the local repository exits.
Then enter the following command to make sure no existing remote origin link exists
git remote remove origin
Once confirmed, the PAT created should be mentioned for the appropriate repository
git remote add origin https://<personal-access-token>@github.com/<my-repo>.git>
git remote add origin https://ghp_2B1FRo1HQRAoevdp3oMEa34PQVuuDX5LYk1f@github.com/johndoe/myrepo.git
After successful completion, you should be able to push the changes from Sourcetree to Github.
P.S: There is a lot more information that needs to be added. I just wanted to make my first post, so here it is! I will be editing it further and add the required information and complete it fully. Thank you.