Can any body solve my error?

[ritikbhatt20]

function fund() public{
    //  Want to set a minimum fund amount in USD 
        // require(msg.value > 1e18, "Didn't send enough"); //value of wei in 1 ethereum
        require(msg.value.getConversionRate() >= MINIMUM_USD, "Didn't send enough");
        // 18 decimals 
        // reverting - undo any action before and send the gas back 
        funders.push(msg.sender);
        addressToAmountFunded[msg.sender] += msg.value;
    }

I am getting this error

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

Please.. Can anypne help me?

[ShawnFromTexas]

I believe you need to set this function to "payable" before public