Plugin: https://wordpress.org/plugins/configure-login-timeout/

Veya,
functions.php 'ye ekleyin;

{code type=php}
 add_filter( 'auth_cookie_expiration', 'keep_me_logged_in_for_1_year' );function keep_me_logged_in_for_1_year( $expirein ) {
 return 31556926;
 }