Below is the sample code of above functionality:-

<apex:page standardController="Account">
    <apex:includeScript value="https://cdnjs.cloudflare.com/ajax/libs/jquery/2.2.4/jquery.min.js" />
    <apex:slds ></apex:slds>
    <apex:form >
        <h1>For Single Field</h1>
    	<apex:inputField value="{!Account.Name}" styleclass="slds-input firstInput"/>
        <br />
        <button type="button" class="slds-button slds-button_brand" onclick="Desabled(); return false;">Desabled</button>
        <button type="button" class="slds-button slds-button_brand" onclick="Enabled(); return false;">Enabled</button>
        <script>
            function Desabled(){
                $('.firstInput')[0].disabled = true;
            }
        
        	function Enabled(){
                $('.firstInput')[0].disabled = false;
            }
        </script>
        <h1>For Multiple Field(jQuery version 1.6+ )</h1>
        <apex:inputField value="{!Account.Name}" styleclass="slds-input allFields"/><br />
        <apex:inputField value="{!Account.AccountSource}" styleclass="slds-input allFields"/><br />
        <br />
        <apex:inputField value="{!Account.AccountNumber}" styleclass="slds-input allFields"/><br />
        <br />
        <button type="button" class="slds-button slds-button_brand" onclick="DesabledAll(); return false;">Desabled</button>
        <button type="button" class="slds-button slds-button_brand" onclick="EnabledAll(); return false;">Enabled</button>
        <br />
        <script>
            function DesabledAll(){
                $('.allFields').prop('disabled',true);
            }
        
        	function EnabledAll(){
                $('.allFields').prop('disabled',false);
            }
        </script>
        
        <h1>For Multiple Field(jQuery version 1.5 and below)</h1>
        <apex:inputField value="{!Account.Name}" styleclass="slds-input allFieldAttr"/><br />
        <apex:inputField value="{!Account.AccountSource}" styleclass="slds-input allFieldAttr"/><br />
        <br />
        <apex:inputField value="{!Account.AccountNumber}" styleclass="slds-input allFieldAttr"/><br />
        <br />
        <button type="button" class="slds-button slds-button_brand" onclick="DesabledAllAttr(); return false;">Desabled</button>
        <button type="button" class="slds-button slds-button_brand" onclick="EnabledAllAttr(); return false;">Enabled</button>
        
        <script>
            function DesabledAllAttr(){
                $('.allFieldAttr').attr('disabled','disabled');
            }
        
        	function EnabledAllAttr(){
                $('.allFieldAttr').removeAttr('disabled');
            }
        </script>
    </apex:form>
</apex:page>

HAPPY LEARNING