GH-900 Study Guide
Markdown-only workbook for Exam GH-900: GitHub Foundations.
Last updated: August 2026. All content is sourced directly from official GitHub and Microsoft documentation.
1. Exam Map And Study Model
The exam domains:
| Domain | Weight | What it means in practice |
|---|---|---|
| Understand Git and GitHub basics | 25–30% | Version control concepts, Git vs GitHub, GitHub Flow, Markdown, accounts |
| Work with GitHub repositories | 10–15% | Repo structure, key files, branches, templates, maintenance |
| Collaborate using GitHub | 10–15% | Issues, PRs, discussions, notifications, Gists, Wikis, Pages |
| Apply modern development practices | 10–15% | GitHub Actions, Copilot, Codespaces, github.dev editor |
| Manage projects with GitHub | 5–10% | Projects, labels, milestones, workflows, insights |
| Understand privacy, security, and administration | 10–15% | 2FA, roles, branch protection, EMUs, org settings |
| Explore the GitHub community | 5–10% | Open source, GitHub Sponsors, Marketplace, InnerSource, forks |
The key is not just knowing definitions. GH-900 expects you to recognize how GitHub features work in practice:
| Concept | What to recognize |
|---|---|
| Repository | Default branch, README, LICENSE, CONTRIBUTING, CODEOWNERS, SECURITY |
| Branch | Feature branch off main, protected branch rules |
| Commit | Snapshot of changes with a message |
| Pull Request | Proposed change from branch to base, linked to issues |
| Issue | Task, bug, feature request — the unit of work |
| GitHub Flow | Branch → commit → PR → review → merge |
| GitHub Actions | Workflow YAML in .github/workflows/, triggers, jobs, steps |
| Copilot | AI code suggestions, Agent Mode, multi-model support |
| Codespaces | Cloud-based dev environment, dev containers |
| Projects | Kanban-style boards for tracking issues and PRs |
2. Domain 1: Understand Git And GitHub Basics (25–30%)
What This Domain Tests
The largest domain. It tests whether you understand version control fundamentals, the difference between Git and GitHub, and how GitHub Flow works in practice. Do not skip this — it is a quarter of the exam.
Version Control Fundamentals
Version control tracks changes to files over time. It lets you:
- Recover previous versions of a file or project.
- Work in parallel with others without overwriting their changes.
- Know who changed what, when, and why.
Git is a distributed version control system. Every developer has a full copy of the repository history locally.
GitHub is a cloud platform built on top of Git. It adds:
- Remote repository hosting.
- Collaboration tools (issues, pull requests, discussions).
- Automation (Actions).
- Security scanning.
- Project management.
Key distinction:
| Git | GitHub |
|---|---|
| Command-line tool | Cloud platform |
| Runs locally | Runs in the browser and cloud |
| Manages versions | Adds collaboration, automation, security |
| Free, open source | Free tier + paid plans |
Core Git Concepts
Repository: A directory tracked by Git. Contains all files and the full history of every change.
Commit: A snapshot of changes at a point in time. Every commit has:
- A unique SHA hash.
- A commit message describing the change.
- An author and timestamp.
Branch: A pointer to a specific commit. Lets you work on changes without touching the main codebase.
main ──── A ──── B ──── C
\
feature-branch D ──── E
Merge: Combining changes from one branch into another. Happens through a pull request on GitHub.
Clone: Copying a remote repository to your local machine.
Fork: Copying someone else's repository to your own GitHub account so you can propose changes.
Pull: Fetching and merging changes from a remote repository into your local branch.
Push: Sending your local commits to the remote repository.
GitHub Accounts And Organizations
| Account type | Description |
|---|---|
| Personal account | Individual GitHub user. Owns repositories. |
| Organization account | Shared account for teams. Owns repos, manages members and billing. |
| Enterprise account | Centrally manages multiple organizations. Used by large companies. |
GitHub Flow
GitHub Flow is the core collaboration model. It has six steps:
- Create a branch from main.
- Make commits on the branch.
- Open a pull request.
- Review and discuss the PR.
- Merge the PR into main.
- Delete the branch.
What to notice:
- Work always happens on a branch, never directly on main.
- The PR is the review and discussion point.
- Merge is the final step after approval.
Markdown
Markdown is used throughout GitHub for:
- README files.
- Issue descriptions and comments.
- Pull request descriptions.
- Discussions.
- Wiki pages.
Key Markdown syntax you should recognize:
# Heading 1
## Heading 2
**bold text**
_italic text_
- bullet item
1. numbered item
[link text](https://example.com)
`inline code`
> blockquote
Task list syntax (used in issues and PRs):
- [x] completed task
- [ ] incomplete task
GitHub Desktop And GitHub Mobile
| Tool | Use when |
|---|---|
| GitHub Desktop | GUI for Git on Mac or Windows. No command line needed. Commit, push, pull, branch. |
| GitHub Mobile | Review and merge PRs on mobile. Triage issues. Notifications. Cannot replace full desktop workflow. |
Domain 1 Traps
- Git and GitHub are not the same thing.
- A fork is not the same as a clone. Fork = copy to your GitHub account. Clone = copy to your local machine.
- Committing to main directly is not GitHub Flow.
- A commit message is not optional — it is the record of why a change was made.