We can use aura:method to invoke lightning controller methods from visualforce page. The below example is to call Lightning Component methods from visualforce page.

Lightning Component:

<!--SampleComponent.cmp--> 
<aura:component implements="flexipage:availableForAllPageTypes,force:appHostable" access="global">
    <!--Aura Method-->
    <aura:method name="welcomeMsgMethod" action="{!c.doAction}" access="global"> 
        <aura:attribute name="message" type="Object" /> 
        <aura:attribute name="name" type="String"/> 
    </aura:method>
    
    <!--Declare Attributes-->
    <aura:attribute name="msg" type="String"/>
    
    <!--Component Start--> 
    <div class="slds-m-around_xx-large">
        <!--Print Welcome Message--> 
        {!v.msg}
    </div>
    <!--Component End-->
</aura:component>

Lightning Controller:

({
    doAction : function(component, event, helper) {
        //Get Parameters
        var params = event.getParam('arguments');
        if (params) {
            //Get Welcome message parameter
            var msg = params.message.message;
            var developerGroup = params.message.developerGroup;
            //Get name parameter
            var name = params.name;
            //Set welcome message and name
            component.set("v.msg", name + ' ' + msg + ' ' + developerGroup);
        }
    }
})

Lightning App:

<!--SampleApp.app--> 
<aura:application extends="ltng:outApp" access="global">
    <!--Lightning component-->
    <aura:dependency resource="c:SampleComponent"/>
</aura:application>

Visualforce Page:

<apex:page>
    <apex:includeLightning />
    <!--Lightning Container-->
    <div style="width:100%;height:100px;" id="LightningContainer" />
    
    <script type="text/javascript">
    var component; //Variable for Lightning Out Component
    //Create Lightning Component
    $Lightning.use("c:SampleApp", function() {
        $Lightning.createComponent("c:SampleComponent", { },
                                   "LightningContainer",
                                   function(cmp) {
                                       component = cmp;
                                       console.log('Component created');
                                   });
    });
    
    //Method to call Lightning Component Method
    var getWelcomeMessage = function(){
        component.welcomeMsgMethod({message : "Welcome to Salesforce Ohana", developerGroup: "Bengaluru"}, "Biswajeet Samal");
    }
    </script>
    
    <apex:form>
        <!--Button to call Javascript method-->
        <apex:commandButton value="Get Welcome Message" onclick="getWelcomeMessage();return false;"/>
    </apex:form>
</apex:page>

Output: