gitea.com

In Gitea, open User Settings → Applications and use Manage Access Tokens to create a token. Choose the needed permission scopes; Gitea shows the token only once. The docs also note tokens can be minted via the API at /api/v1/users/{username}/tokens using HTTP Basic auth with your username and password.

Sign in to your Gitea account at gitea.com login. The API docs state HTTP Basic authentication is supported, and that creating tokens via /api/v1/users/{username}/tokens specifically requires Basic auth with your username and password.

Add an SSH public key or SSH certificate to your Gitea account in User Settings → SSH / GPG Keys. Then sign API requests with the matching private key using the draft-cavage HTTP Signatures format; send the signature in the Signature header, and include x-ssh-certificate when using an SSH certificate.

Register an OAuth2 application in Gitea from User Settings → Applications or, for admins, the instance application pages described in the docs. Create an app with a name and redirect URL, then copy the generated Client ID and Client Secret. Use those in the standard OAuth flow against Gitea’s OAuth endpoints; user consent is required.