Getting error in a function

[C191068]

function fund() public  {
     
     //as we want to convert msg.value to USD we made the following changes
       
        require(msg.value.getConversionRate() >= MINIMUM_USD , "Not send enough");// to get accees to the 'value' at deploy at run transaction tab
        //1e18 is 1 ether, here the value must be greater than 1 ether
        //require is a checker it checks whether the value is greater than 1 ether
        // if not it is going to revert with an error messsage shown above
        //adding funders to the array 
         funders.push(msg.sender);
         addressToAmountFunded[msg.sender] = msg.value;// It is for when somebody funds our contract

    }// To send money. We made it public so that anybody can call it

On the above function I am running into an error

TypeError: "msg.value" and "callvalue()" can only be used in payable public functions

Can anyone please help ?

[alfaqi]

add payable to the function declaration
function fund() public payable{