What are the main HTTP methods you know and what are they used for?

Main HTTP methods and their purpose:

• GET — request a resource. Used to retrieve data from the server. Should not change the state.
• POST — send data to the server, usually for creating new resources or performing actions.
• PUT — replace or create a resource at the specified URI. Idempotent (repeated requests give the same result).
• DELETE — delete a resource.
• HEAD — request headers of a resource without the body. Allows checking existence and metadata.
• OPTIONS — request supported server methods for a resource.
• PATCH — partial update of a resource.

Example:

GET /users/123 HTTP/1.1
Host: example.com

POST /users HTTP/1.1
Host: example.com
Content-Type: application/json

{"name": "Иван"}

Each method has its semantic meaning and should be used according to the specification for proper REST API operation.