VS Code highlighted all my wordpress function name

You have to add “wordpress” to the intelephense.stubs array setting in your VS Code settings file. This array should probably also have many other stubs listed as well. For example: (“wordpress” is at the bottom)

//  VS Code settings.json
{
    // ... other settings here ...
    "intelephense.files.maxSize": 3000000,
    "intelephense.stubs": [
        "apache",
        "bcmath",
        "bz2",
        "calendar",
        "com_dotnet",
        "Core",
        "ctype",
        "curl",
        "date",
        "dba",
        "dom",
        "enchant",
        "exif",
        "FFI",
        "fileinfo",
        "filter",
        "fpm",
        "ftp",
        "gd",
        "gettext",
        "gmp",
        "hash",
        "iconv",
        "imap",
        "intl",
        "json",
        "ldap",
        "libxml",
        "mbstring",
        "meta",
        "mysqli",
        "oci8",
        "odbc",
        "openssl",
        "pcntl",
        "pcre",
        "PDO",
        "pdo_ibm",
        "pdo_mysql",
        "pdo_pgsql",
        "pdo_sqlite",
        "pgsql",
        "Phar",
        "posix",
        "pspell",
        "readline",
        "Reflection",
        "session",
        "shmop",
        "SimpleXML",
        "snmp",
        "soap",
        "sockets",
        "sodium",
        "SPL",
        "sqlite3",
        "standard",
        "superglobals",
        "sysvmsg",
        "sysvsem",
        "sysvshm",
        "tidy",
        "tokenizer",
        "xml",
        "xmlreader",
        "xmlrpc",
        "xmlwriter",
        "xsl",
        "Zend OPcache",
        "zip",
        "zlib",
        "wordpress"
    ]
}

You can also take a look at these github issues:

• Include wordpress stubs that can be enabled in intelephense.stubs #833
• [DOC]: Better way to get WordPress intellisense #2