Hey! I need help with an error in solidity

[CoderB01]

function fund() public {
        require(msg.value.getConversionRate() >= MINIMUM_USD, "Not enough Ethereum"); // 1eth == 1 * 10 ** 10 == 1.000000000000000000 wei
        funders.push(msg.sender);
        amountFundedbyAddress[msg.sender] = msg.value;
    }

On this function i am having this error:

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

Can someone tell me what's going on?

[CoderB01]

Just add payable to your function

[AmitKochar1]

function fund() public payable {
require(msg.value.getConversionRate() >= MINIMUM_USD, "Not enough Ethereum"); // 1eth == 1 * 10 ** 10 == 1.000000000000000000 wei
funders.push(msg.sender);
amountFundedbyAddress[msg.sender] = msg.value;
}