add_submenu_page(
    "pharma-plugin", // parent slug
    "All Trade Name", // page title
    "All Trade Name", // menu title
    "manage_options", // capability = user_level access
    "all-trade-name", // menu slug
    "all_trade_name" // callback function
);

<input placeholder="Enter product name" type="search" name="s" title="Search" value="">