fieldAccessExplorer.html

<template>
    <lightning-card>
        <div class="divcenter">SalesforceCodex Field's Access Explorer</div>
      
        <lightning-layout multiple-rows>
                    <lightning-layout-item size="2" padding="around-small">
                           <lightning-combobox name="objectName" 
                            label="Object"
                            value="" 
                            placeholder="Select Object" 
                            options={objects} 
                            onchange={handleObjectChange}
                            required></lightning-combobox>
                    </lightning-layout-item>
                    <lightning-layout-item size="2" padding="around-small">
                            <lightning-combobox
                            name="Fields"
                            label="Fields"
                            value=""
                            placeholder="Select Field"
                            options={fields}
                            onchange={handleFieldChange}
                            required
                    ></lightning-combobox>
                    </lightning-layout-item>
        </lightning-layout>
        </lightning-card>
</template>

fieldAccessExplorer.js

import { LightningElement, track, wire} from 'lwc';
import getObjects from '@salesforce/apex/FieldExplorerController.getObjects';
import getFields from '@salesforce/apex/FieldExplorerController.getFields';

export default class FieldAccessExplorer extends LightningElement {
    @track objects = [];
    @track fields = [];
    @wire(getObjects)
    wiredMethod({ error, data }) {
        if (data) {
            this.dataArray = data;
            let tempArray = [];
            this.dataArray.forEach(function (element) {
                var option=
                {
                    label:element,
                    value:element
                };
                tempArray.push(option);
            });
            this.objects=tempArray;
        } else if (error) {
            this.error = error;
        }
    } 
    
    handleObjectChange(event)
    {   
        const selectedOption = event.detail.value;  
        getFields({ objectName: selectedOption})
        .then(result => {
            this.dataArray = result;
            let tempArray = [];
            this.dataArray.forEach(function (element) {
                var option=
                {
                    label:element.Label,
                    value:element.Name
                };
                tempArray.push(option);
            });
            this.fields=tempArray;
        })
        .catch(error => {
            this.error = error;
        });

    }
    handleFieldChange(){

    }
}

fieldAccessExplorer.js-meta.xml

<?xml version="1.0" encoding="UTF-8"?>
<LightningComponentBundle xmlns="http://soap.sforce.com/2006/04/metadata" fqn="fieldAccessExplorer">
    <apiVersion>47.0</apiVersion>
    <isExposed>true</isExposed>
    <targets>
        <target>lightningCommunity__Page</target>
        <target>lightningCommunity__Default</target>
        <target>lightning__RecordPage</target>
        <target>lightning__AppPage</target>
        <target>lightning__HomePage</target>
    </targets>
</LightningComponentBundle>