tramp is initially configured to use the scp program to connect to the remote host. Just type C-x C-f and then enter file name /user@host:/path/to.file. For details, see See Default Method.
For problems related to the behavior of remote shell, see Remote shell setup for details.
For changing the connection type and file access method from the defaults to one of several other options, see (see Connection types).
Note that some user options and variables described in these examples are not auto loaded by Emacs. All examples require tramp is installed and loaded: