Sample Code:

HTML:

<template>
    <div class="slds-box slds-theme--default">
        <table class="slds-table slds-table_cell-buffer slds-table_bordered slds-table_striped">
            <thead>
                <tr class="slds-line-height_reset">
                    <th class="" scope="col">
                        Account Name
                    </th>
                    <th class="" scope="col">
                        Account Number
                    </th>
                    <th class="" scope="col">
                        Owner
                    </th>
                </tr>
            </thead>
            <tbody>
                <template iterator:it={records}>
                    <tr class="slds-hint-parent" key = {it.value.Id}>
                        <td data-label="Account Name">
                            <div class="slds-cell-wrap">{it.value.Name}</div>
                        </td>
                        <td data-label="Account Number">
                            <div class="slds-cell-wrap">{it.value.AccountNumber}</div>
                        </td>
                        <td data-label="Owner">
                            <div class="slds-cell-wrap">{it.value.OwnerName}</div>
                        </td>
                    </tr>
                </template>
            </tbody>
        </table>
    </div>
</template>

JavaScript:

import { LightningElement, wire } from 'lwc';
import fetchAccounts from '@salesforce/apex/AccountController.fetchAccounts';

export default class Sample extends LightningElement {

    records;
    error;

    @wire( fetchAccounts )  
    wiredAccount( { error, data } ) {
        if ( data ) {

            let rows = JSON.parse( JSON.stringify( data ) );
                
            for ( let i = 0; i < rows.length; i++ ) {  

                let dataParse = rows[ i ];

                if ( dataParse.hasOwnProperty( "Owner" ) ) {

                    if ( dataParse.Owner.hasOwnProperty( "Name" ) )
                        dataParse.OwnerName = dataParse.Owner.Name;

                }
                
            }
                
            this.records = rows;
            this.error = undefined;

        } else if ( error ) {

            this.error = error;
            this.records = undefined;

        }
    }  

}

Apex Class:

public with sharing class AccountController {
 
    @AuraEnabled( cacheable = true )
    public static List< Account > fetchAccounts() {
     
        return [ SELECT Id, Name, Industry, Rating, Type, AccountNumber, Phone, Owner.Name FROM Account LIMIT 10 ];
         
    }
     
}

Output: