This section explains how to concatenate strings in Solidity.
Syntax
To concatenate strings in Solidity, do the following.
string(abi.encodePacked(string1, string2 [, ...[, stringN]]))
Sample Code
// SPDX-License-Identifier: GPL-3.0
pragma solidity >=0.7.0 <0.9.0;
contract Test {
function strConcat(string memory str1, string memory str2) public pure returns(string memory) {
// concatenate strings
return string(abi.encodePacked(str1, str2));
}
}

Since EVM (Ethereum Virtual Machine) cannot directly handle strings, the string manipulation in Solidity requires the use of abi.encodePacked() to encode ABI to convert the string to a form that EVM can handle.