Permission Denied for mkdir() php in Docker

When i Run my php code in docker for mkdir it says this in the browser

Warning: mkdir(): Permission denied in /var/www/html/test.php on line 9

Warning: mkdir(): Permission denied in /var/www/html/test.php on line 12

I have been searching but can’t get any suitable source for my use. How can i allow docker to give permission to my php or what is the solution?

Here is my php code

<?php
$postk = "1220";
$root = "login/";
$room_id = "foile";
$NewRoot = "movie";

if (!file_exists($root . $postk)) {
    $dirPathp = $root . $postk;
    $resultp = mkdir($dirPathp, 0777, true);

    $dirPathpr = $root . $postk . "/" . $room_id;
    $resultpr = mkdir($dirPathpr, 0777, true);

} else {
    $dirPathpr = $root . $postk . " / " . $room_id;
    $resultpr = mkdir($dirPathpr, 0777, true);
} ?>

Here is my Docker File

FROM php:7.3-apache

#Install git and Mysql Extensions for php

RUN apt-get update && apt-get install -y git
RUN docker-php-ext-install pdo pdo_mysql mysqli
RUN a2enmod rewrite

COPY . /var/www/html/
EXPOSE 80/tcp
EXPOSE 443/tcp

Here is Docker compose file

version: '3.8'

volumes:
  datafiles:

services:

  mysql:
    image: mysql:8.0.0
    container_name: mysql6
    environment:
      - MYSQL_ROOT_PASSWORD=sopno_1818120**
      - MYSQL_TCP_PORT=3306
      - TZ=Asia/Dhaka
    volumes:
      - datafiles:/var/lib/mysql
    restart: always

  website:
    container_name: php6
    build:
      context: .
      dockerfile: Dockerfile
    environment:
      - DB_HOST=mysql
      - MYSQL_DBPORT=3306
      - DB_USERNAME=sopnobari_tuneb
      - DB_PASSWORD=sopno_1818120**
      - DB_NAME=sopnobari_sopno
    ports:
      - "3050:80"
      - "3051:443"
    depends_on:
      - mysql