How to convert the code of Header output status in PHP

According to Mr. Peng Wuxing's PHP Le, the header can send the Status header, as shown in In this way, the user's browser can see the 404 error that the file cannot be found, but I tried this. Later, I checked the relevant http information on w3.org and finally found out how to output the Status code (Status) in the Header to share with you. It should be like this: Header ("http/1.1 403 Forbidden");?> The first part is the HTTP Version. The second part is the Status code. The third part is the Reason-Phrase, there cannot be carriage return in the middle. The first part and the second part are required. The third part is for people to see. It can be written, not written, or even written in disorder. Also, the output of this sentence must be in the first line of the Html file. Below I will show the meaning of each code (it is found on w3.org and authoritative): * 1xx: Informational-Request received, continuing process * 2xx: success-The action was successfully received, understood, and accepted * 3xx: Redirection-Further action must be taken in order to complete the request * 4xx: client Error-The request contains bad syntax or cannot be fulfilled * 5xx: Server Error-The server failed to fulfill an apparently valid request | "100"; Continue | "101 "; switching Protocols | "200"; OK | "201"; Created | "202"; Accepted | "203"; Non-Authoritative Information | "204 "; no Content | "205"; Reset Content | "206"; Partial Content | "300"; Multiple Choices | "301"; Moved Permanently | "302 "; moved Temporarily | "303"; See Other | "304"; Not Modified | "305"; Use Proxy | "400"; Bad Request | "401 "; unauthorized | "402"; Payment Required | "403"; Forbidden | "404"; Not Found | "405"; Method Not Allowed | "406 "; not Acceptable | "407"; Proxy Authentication Required | "408"; Request Time-out | "409"; Conflict | "410"; Gone | "411 "; length Required | "412"; Precondition Failed | "413"; Request Entity Too Large | "414"; Request-URI Too Large | "415 "; unsupported Media Type | "500"; Internal Server Error | "501"; Not Implemented | "502"; Bad Gateway | "503"; Service Unavailable | "504 "; gateway Time-out | "505"; HTTP Version not supported