Getter functions can be declared view or pure.

View function declares that no state will be changed.

Pure function declares that no state variable will be changed or read.

// SPDX-License-Identifier: MIT
pragma solidity ^0.7.3;

contract ViewAndPure {
    uint public x = 1;

    // Promise not to modify the state.
    function addToX(uint y) public view returns (uint) {
        return x + y;
    }

    // Promise not to modify or read from the state.
    function add(uint i, uint j) public pure returns (uint) {
        return i + j;
    }
}