Controller:

Public with sharing class Sample {
    
    Public string myInput{get;set;}
    Public string myOutput{get;set;}
    
    Public void myMethod(){
        myOutput = myInput;
    }
}

Visualforce Page:

<apex:page controller="Sample">
    <!--Pass parameters from visualforce page to controller-->
    <apex:form>
        <apex:pageblock >
            Input Here - <apex:inputText value="{!myInput}"/>
            <apex:commandButton value="Submit" reRender="outputID" action="{!MyMethod}"/> 
        </apex:pageblock>
        <apex:pageblock >
            <b>Output Here - </b><apex:outputText value="{!myOutput}" id="outputID">
            </apex:outputText>
        </apex:pageblock>
    </apex:form>
</apex:page>

Output: